MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING

                                20 WILLIAM STREET
                                40 WILLIAM STREET
                                45 WILLIAM STREET
                                55 WILLIAM STREET
                                60 WILLIAM STREET
                                65 WILLIAM STREET
                                80 WILLIAM STREET
                               100 WILLIAM STREET

                            WELLESLEY, MASSACHUSETTS




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                 MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING

                                TABLE OF CONTENTS
                                -----------------

                                                                           Page

  1.     Payment of Indebtedness .............................. ..............9
  2.     Covenants of Title..................................................10
  3.     Usury ..............................................................13
  4.     Impositions ........................................................13
  5.     Tax Deposits....................................................... 15
  6.     Change in Taxes.................................................... 19
  7.     Insurance ......................................................... 20
  8.     Insurance/Condemnation Proceeds ....................................24
  9.     Restoration Following Fire and Other Casualty
          or Condemnation....................................................26
 10.     Disposition of Condemnation or Insurance
          Proceeds ..........................................................34
 11.     Fire and Other Casualty; Self-Help..................................37
 12.     Rent Insurance Proceeds ............................................38
 13.     Intentionally Omitted ..............................................39
 14.     Repair; Alterations; Waste; Environmental ..........................39
 15.     Environmental Indemnification ......................................49
 16.     Independence of Security ...........................................49
 17.     No Other Liens......................................................50
 18.     Management..........................................................51
 19.     Ground Lease .......................................................52
 20.     Sidewalks, Municipal Charges  ......................................52
 21.     Assignment of Rents and Leases  ....................................53
 22.     Future Leases ......................................................56
 23.     Mortgagors's Obligations as Lessor .................................62
 24.     Leases; Foreclosure ................................................63
 25.     Intentionally Deleted ..............................................64
 26.     Events of Default ..................................................64
 27.     Remedies Upon Default ..............................................74
 28.     Acceleration Interest ..............................................80
 29.     Late Charge ........................................................81
 30.     Waiver of Statutory Rights..........................................81
 31.     Security Interest ..................................................82
 32.     Right of Entry......................................................83
 33.     Estoppel Certificate................................................84
 34.     Annual Statements ..................................................84
 35.     Rights Cumulative ..................................................86
 36.     Subrogation ........................................................86
 37.     No Waiver ..........................................................87
 38.     Mortgage Extension .................................................87
 39.     Indemnification ....................................................88
 40.     Scope of Liability..................................................88
 41.     Attorneys' Fees ....................................................88
 42.     Administrative Fees ................................................89
 43.     Protection of Security; Cost and Expenses...........................90


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                 MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING

                          TABLE OF CONTENTS (Continued)
                          -----------------
                                                                            Page

 44.     Notices ............................................................92
 45.     Release/Partial Release.............................................93
 46.     Applicable Law .....................................................97
 47.     Invalidity..........................................................97
 48.     Captions............................................................98
 49.     Modifications ......................................................98
 50.     Bind and Inure......................................................98
 51.     Replacement of Note ................................................98
 52.     Time of the Essence ................................................99
 53.     Statutory Condition; Statutory Power of Sale .......................99
 54.     ERISA...............................................................99



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Recording Requested By and
When Recorded Return to:

Nutter, McClennen & Fish
One International Place
Boston, MA  02110-2699
Attn:  Robert A. Fishman, Esq.



                 MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING



     THIS MORTGAGE is made as of the 8th day of January, 1996, by WELLESLEY 
HOLDING, L.P. ("Wellesley I"), WELLESLEY HOLDING II, L.P. ("Wellesley II") and 
BEACON PROPERTIES, L.P. ("BPLP"), each of which is a Delaware limited 
partnership, and each of which has a principal place of business at 50 Rowes 
Wharf, Boston, Massachusetts 02110 (Wellesley I, Wellesley II and BPLP are 
singly each hereinafter referred to as a "Mortgagor" and collectively 
hereinafter referred to as "Mortgagors") to CONNECTICUT GENERAL LIFE INSURANCE 
COMPANY, a Connecticut corporation having its principal place of business at 900
Cottage Grove Road, Bloomfield, Connecticut 06002 (hereinafter referred to as
"Mortgagee").

                              W I T N E S S E T H:

     THAT, to secure (i) payment to Mortgagee of the principal indebtedness of
Fifty-Five Million and No/100 Dollars ($55,000,000) together with interest
thereon, as evidenced by that certain promissory note (hereinafter referred to
as the "Note") of even date herewith, and any renewals, extensions or
modifications thereof (including, without limitation, any modification
increasing the interest rate, the principal amount, the monthly payments or
extending the maturity date) given by

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Mortgagors to Mortgagee and made payable to the order of Mortgagee, with the
final payment being due and payable on February 1, 2003 (the "Maturity Date"),
in and by which Note Mortgagors promise to pay the said principal indebtedness
and interest at the rate and in installments as provided in the Note (the loan
represented and evidenced by the Note is referred to as the "Loan"), (ii) the
performance of the covenants herein contained and the payment of any monies
expended by Mortgagee in connection therewith, (iii) the payment of all
obligations and the performance of all covenants of Mortgagors under any other
loan documents, agreements or instruments between Mortgagors and Mortgagee given
in connection with or related to this Mortgage or the Note, and (iv) any and all
additional advances made by Mortgagee to protect or preserve the Security
(hereinafter defined) or the security interest created hereby on the Security,
or for taxes, assessments, or insurance premiums as hereinafter provided or for
performance of any of Mortgagors' obligations hereunder or for any other purpose
provided herein (whether or not the original Mortgagors remain the owner of the
Security at the time of such advances) (all of the aforesaid indebtedness and
obligations of Mortgagors from time to time outstanding being herein called the
"Indebtedness", and all of the documents, agreements and instruments between
Mortgagors and Mortgagee or given by Mortgagors in favor of Mortgagee now or
hereafter evidencing or securing the repayment of, or otherwise pertaining to,
the Indebtedness being herein collectively called the "Loan Documents"),
Mortgagors do hereby mortgage, grant with MORTGAGE COVENANTS, bargain, sell,
assign, pledge, transfer, and convey unto Mortgagee and to Mortgagee's
successors and assigns forever,


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all of the following described land, improvements, real and personal property,
rents and leases, and all of its estate, right, title and interest therein
(hereinafter collectively called the "Security"):

     The land described in Exhibit A attached hereto and made a part hereof,
situate, lying and being in the Town of Wellesley, County of Norfolk, and
Commonwealth of Massachusetts (the "Land");

     TOGETHER with all buildings and other improvements now or hereafter located
on said Land or any part thereof including but not limited to, all extensions,
betterments, renewals, renovations, substitutions and replacements of, and all
additions and appurtenances to, the Security (the "Improvements");

         TOGETHER with all of the right, title and interest of Mortgagors in and
to the land lying in the bed of any street, road, highway or avenue in front of
or adjoining the Land to the center lines thereof;

     TOGETHER with the right to use, in perpetuity, in connection with the
operation of the Security the names "Wellesley Office Park", "20 William
Street", "40 William Street", 45 William Street", "55 William Street", "60
William Street", "65 William Street", "80 William Street", "100 William Street"
and any other names similar thereto (provided, however, that notwithstanding
anything to the contrary contained in any of the Loan Documents, the parties
acknowledge and agree that 100 William Street is not


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part of Wellesley Office Park, so called, but is immediately adjacent thereto);

     TOGETHER with the benefit of and subject to those of the Permitted
Encumbrances (as hereinafter defined) listed in Part I of Exhibit B attached
hereto and made a part hereof, including, without limitation, all easements now
or hereafter located on or appurtenant to the Land and/or Improvements, or under
or above the same or any part thereof, and together with all rights-of-way and
(to the extent assignable) all licenses, permits, approvals and privileges,
belonging or in any way appertaining to the Land and/or Improvements including
without limitation (i) any drainage ponds or other like drainage areas not
located on the Land which may be required for water run-off, (ii) any easements
necessary to obtain access from the Land to such drainage areas, or to any other
location to which Mortgagors have a right to drain water or sewage, (iii) any
land required to be maintained as undeveloped land by the zoning rules and
regulations applicable to the Land, and (iv) any easements and agreements which
are or may be established to allow satisfactory ingress to, egress from and
operation of the Land and/or the Improvements;

     TOGETHER with any and all awards hereafter to be made by any municipal or
other governmental authorities to the present and all subsequent owners of the
Security for the taking of all or any portion of the Security by power of
eminent domain, including, without limitation, awards for damage to the
remainder of the Security and any awards for any change or changes of grade of
streets affecting the Security, which said awards are hereby


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assigned to Mortgagee, and Mortgagee, at its option, is hereby authorized,
directed and empowered (subject to Section 8 below) to collect and receive the
proceeds of any such awards from the authorities making the same and to give
proper receipts and acquittances therefor, and to apply the same in accordance
with the applicable provisions of this Mortgage (all of the foregoing Land,
Improvements, rights, easements, rights-of-way, licenses, privileges, and
awards, collectively, the "Real Property");

     TOGETHER with all proceeds, insurance or otherwise, paid for the damage
done to any of the Security and all proceeds of the conversion, voluntarily or
involuntarily, of any of the Security into cash or liquidated claims;

     TOGETHER with all fixtures, machinery, equipment, goods, and every other
article of personal property, tangible and intangible, now or hereafter attached
to or used in connection with the Real Property, or placed on any part thereof
and whether or not attached thereto, appertaining or adapted to the use,
management, operation or improvement of the Real Property, insofar as the same
and any reversionary right thereto may now or hereafter be owned or acquired by
one or more of the Mortgagors (as more completely described in this paragraph
and the next following paragraph, the "Personal Property"), including, but
without limitation: all partitions; screens; awnings; shades; blinds; floor
coverings; hall and lobby equipment; heating, lighting, plumbing, ventilating,
refrigerating, incinerating, elevator, escalator, air conditioning and
communication plants or systems with appurtenant fixtures; vacuum cleaning
systems; call


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systems; sprinkler systems and other fire prevention and extinguishing apparatus
and materials; all equipment, manual, mechanical and motorized, for the
construction, maintenance, repair and cleaning of, and removal of snow from,
parking areas, walks, underground ways, truck ways, driveways, common areas,
roadways, highways and streets; all equipment, manual, mechanical and motorized,
for the transportation of customers or employees to and from the facilities on
the Real Property; all telephone, computer and other electronic equipment and
appurtenances thereto, including software; and all other machinery, pipes,
poles, appliances, equipment, wiring, fittings, panels and fixtures; and any
proceeds therefrom, any replacements thereof or additions or accessions thereto;
all of Mortgagors' rights, but not Mortgagors' obligations, under Mortgagors'
leases for Personal Property; all contract rights held by Mortgagors from time
to time in existence of whatever nature relating to the Real Property or
Personal Property, including, but not limited to, architectural and engineering
plans, drawings, tests, reports or studies, contracts for goods or services and
management contracts, all warranties and guaranties under such contracts and
rights under insurance policies; all rights of Mortgagors under architect's
contracts, construction contracts, completion bonds, performance bonds and
payment bonds related to the Real Property or Personal Property; all accounts,
accounts receivable, parking garage revenues and receivables, contract rights,
general intangibles, documents, instruments and chattel paper arising from or in
connection with the Real Property or Personal Property, including all books and
records in connection therewith and reserve accounts required to be established
now or at any


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time in the future under the Loan Documents, and all proceeds of any and all of
the same; all rights under all causes of action held by Mortgagors related to
the Real Property or Personal Property, including claims relating to
construction or the condition of the Improvements; all of Mortgagors' right,
title and interest in and to all artwork and sculpture located on the Real
Property; and all building materials, supplies and other property delivered to
the Real Property for incorporation into the Improvements thereon, all of which,
to the extent permitted by law, are declared to be a part of the realty and
covered by the lien hereof, but said lien shall not cover any fixture,
machinery, equipment or article of personal property which is owned by a tenant
and which can be removed from the Real Property by the tenant, but said lien
shall include any other fixture, machinery, equipment or article of personal
property incorporated into the improvements so as to constitute realty under
applicable law;

     TOGETHER with all of Mortgagors' books of account and records relating to
the Security, including all computers and software relating thereto;

     TOGETHER with all contracts of sale and leases in the nature of a sale of
the Real Property, or any portion thereof, now and hereafter entered into and
all right, title and interest of Mortgagors thereunder, including, without
limitation, cash or securities deposited thereunder to secure performance by the
contract purchasers, which deposits Mortgagors may retain unless an Event of
Default (as hereinafter defined) exists hereunder;


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all licenses, permits, franchises, governmental approvals and all sanitary
sewer, drainage, water and utility service agreements, reservations and
capacities benefiting the Real Property or any part thereof; and all rights of
Mortgagors under any covenants, agreements, easements, restrictions or
declarations relating to, or as an appurtenance to, the Real Property or the
Personal Property or any part thereof;

     TOGETHER with all leases, subleases, licenses, concession agreements,
occupancy agreements or grants of other possessory interests now or hereafter in
force or effect, oral or written, and all renewals, extensions, modifications,
replacements and guaranties thereto affecting all or any part of the Land or
Improvements;

     TOGETHER with all rents, issues, revenues, profits and income from the Real
Property and Personal Property;

     TOGETHER with all of the right, title and interest of Mortgagors in and to
all and singular the tenements, hereditaments and appurtenances belonging to or
in any way pertaining to the Security; all the estate, right, title and claim
whatsoever of Mortgagors, either in law or in equity, in and to the Security;
and any and all other, further or additional title, estate, interest or right
which may at any time be acquired by Mortgagors in or to the Security, and if
one or more of the Mortgagors shall at any time acquire any further estate or
interest in or to the Security, the lien of this Mortgage shall attach, extend
to, cover and be a lien upon such further estate



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or interest automatically without further instrument or instruments, and
Mortgagors, upon request of Mortgagee, shall execute such instrument or
instruments as shall reasonably be requested by Mortgagee to confirm such lien,
subject to the limitations on Mortgagors' liability set forth in Section 40
below;

     TO HAVE AND TO HOLD the Security, and each and every part thereof, unto
Mortgagee and its successors and assigns forever, for the purposes and uses
herein set forth.

     AND, Mortgagors each hereby further covenant, agree and warrant (as
applicable) as follows:

     l. Payment of Indebtedness. Mortgagors will pay the principal indebtedness
and interest thereon in accordance with the provisions of the Note and all
prepayment fees, late charges and fees required thereunder, and all extensions,
renewals, modifications, amendments and replacements thereof, and will keep and
perform all the covenants, promises and agreements, and pay all sums provided in
(i) each of the Note or any other promissory note or notes at any time hereafter
issued by Mortgagors to evidence the Indebtedness, (ii) this Mortgage, and (iii)
any and all other Loan Documents, all in the manner herein or therein set forth.
Subject to the limitations of liability set forth in Section 40 of this Mortgage
and Section 16 of the Note, Mortgagors shall each be fully liable for such
payment and performance. If more than one corporation, partnership, trust,
limited liability company or other entity or person shall in the


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future execute this Mortgage as one of the Mortgagors or shall directly assume
some or all of the obligations of Mortgagors hereunder, whether as a result of a
transfer of an interest in the Security permitted by the Loan Documents, or
otherwise as may be agreed to in writing by Mortgagee, then each such entity and
person shall be jointly and severally liable for the satisfaction of all
obligations and duties of Mortgagors under this Mortgage, subject to the
limitations of liability set forth in Section 40 of this Mortgage and Section 16
of the Note.

     2. Covenants of Title. Wellesley I has good and indefeasible title to the
entire Wellesley I Parcels (as hereinafter defined) in fee simple, has absolute
title to Wellesley I's Personal Property (except as to personal property which
is leased by Wellesley I, as to which Wellesley I shall have good title to the
lessee's interest under the leases), and has good right and full power to sell,
mortgage and convey the same; the Wellesley I Parcels and the balance of the
Wellesley I portion of the Security are free and clear of easements,
restrictions, liens, leases and encumbrances, except those easements,
restrictions, liens, leases and encumbrances related to the Wellesley I Parcels
listed on Exhibit B hereto or which may hereafter be created and be permitted to
continue to exist pursuant to the terms hereof; and Wellesley I will warrant and
defend title to the Wellesley I portion of the Security against all claims and
demands whatsoever except the Permitted Encumbrances (defined hereinbelow)
related to the Wellesley I Parcels. The "Wellesley I Parcels" shall mean the
parcels of


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land with the buildings and other improvements thereon described as "Parcel I"
on Exhibit A hereto.

     Wellesley II has good and indefeasible title to the entire Wellesley II
Parcel (as hereinafter defined) in fee simple, has absolute title to Wellesley
II's Personal Property (except as to personal property which is leased by
Wellesley II, as to which Wellesley II shall have good title to the lessee's
interest under the leases), and has good right and full power to sell, mortgage
and convey the same; the Wellesley II Parcel and the balance of the Wellesley II
portion of the Security are free and clear of easements, restrictions, liens,
leases and encumbrances, except those easements, restrictions, liens, leases and
encumbrances related to the Wellesley II Parcel listed on Exhibit B hereto or
which may hereafter be created and be permitted to continue to exist pursuant to
the terms hereof; and Wellesley II will warrant and defend title to the
Wellesley II portion of the Security against all claims and demands whatsoever
except the Permitted Encumbrances related to the Wellesley II Parcel. The
"Wellesley II Parcel" shall mean the parcel of land with the buildings and other
improvements thereon described as "Parcel V" on Exhibit A hereto.

     BPLP has good and indefeasible title to the entire BPLP Parcels (as
hereinafter defined) in fee simple, has absolute title to BPLP's Personal
Property (except as to personal property which is leased by BPLP, as to which
BPLP shall have good title to the lessee's interest under the leases), and has
good right and full power to sell, mortgage and convey the same; the BPLP


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Parcels and the balance of the BPLP portion of the Security are free and clear
of easements, restrictions, liens, leases and encumbrances, except those
easements, restrictions, liens, leases and encumbrances related to the BPLP
Parcels listed on Exhibit B hereto or which may hereafter be created and be
permitted to continue to exist pursuant to the terms hereof; and BPLP will
warrant and defend title to the BPLP portion of the Security against all claims
and demands whatsoever except the Permitted Encumbrances related to the BPLP
Parcels. The "BPLP Parcels" shall mean the parcels of land with the buildings
and other improvements thereon described as "Parcel II," "Parcel III" and
"Parcel IV" on Exhibit A hereto.

     Those easements, restrictions, liens, leases and encumbrances listed on
Exhibit B hereto which relate to the Wellesley I Parcels, the Wellesley II
Parcel and the BPLP Parcels, or which may hereafter be created and be permitted
to continue to exist pursuant to the terms hereof, are collectively herein
referred to as the "Permitted Encumbrances". The Permitted Encumbrances also
include leases and lease amendments hereafter entered into by Mortgagors (or any
of them) in accordance with Section 22 hereof. Mortgagee shall have the right,
at its option and at such time or times as it shall deem necessary, to take
whatever action it may deem necessary to defend or uphold the lien of this
Mortgage or otherwise enforce any of the rights of Mortgagee hereunder or any
obligation secured hereby, including without limitation, the right to institute
appropriate legal proceedings for such purposes.



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     3. Usury. It is hereby expressly agreed that if from any circumstances
whatsoever fulfillment of any provision of the Note, this Mortgage, or any other
Loan Documents, at the time performance of such provision shall be due, shall
involve transcending the limit of validity presently prescribed by any
applicable usury statute or any other law, with regard to obligations of like
character and amount, then ipso facto the obligation to be fulfilled shall be
reduced to the limit of such validity, so that in no event shall any exaction be
possible under the Loan Documents that is in excess of the limit of such
validity. In no event shall Mortgagors be bound to pay for the use, forbearance
or detention of the money loaned pursuant to the Loan Documents, interest of
more than the current applicable legal limit, if any; the right to demand any
such excess being hereby expressly waived by Mortgagee.

     4. Impositions. Subject to the right of Mortgagors (or any of them) to
contest an Imposition (as hereinafter defined) as set forth below and subject to
Section 5 below, Mortgagors shall pay, before the last day on which the same may
be paid without penalty or interest, all real estate taxes, sewer rents, water
charges, municipal electric and all other municipal and governmental
assessments, rates, charges, impositions and liens (hereinafter referred to as
"Impositions") which now or hereafter are imposed by law upon the Security.
Subject to the contest rights hereinafter provided for, if any Imposition is not
paid within the time hereinabove specified, Mortgagee shall have the right to
pay the same, together with any penalty and interest thereon, and the amount or
amounts so paid or advanced shall


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forthwith be payable by Mortgagors to Mortgagee and shall be secured by the lien
of this Mortgage; but Mortgagors (or any of them) may in good faith contest, at
their (or its) own cost and expense, by proper legal proceedings, the validity
or amount of any Imposition, on the condition that the Mortgagor(s) in question
first shall deposit with Mortgagee or a mutually satisfactory escrow agent
pursuant to a mutually satisfactory agreement, as security for the payment of
such contested item, an amount equal to the contested item plus all penalties
and interest which would be payable if Mortgagors (or any of them) are
ultimately required to pay such contested item (with due credit to Mortgagors
for interest which will accrue on such deposit if held by such escrow agent,
Mortgagee hereby agreeing to permit such escrow agent to invest the same at
Mortgagors' direction in the investments permitted under the Tax Escrow
Agreement (as defined in Section 5 hereof) unless an Event of Default exists
hereunder, in which event Mortgagee shall direct such investments), and on the
further condition that no amount so contested may remain unpaid for such length
of time as shall permit the Security, or the lien thereon created by the item
being contested, to be sold for the nonpayment thereof, or as shall permit an
action of foreclosure or the like to be commenced by the holder of any such
lien. In the event that there is not an escrow agent, any deposit required
hereunder shall be deposited with Mortgagee to be held in a service account
which is non-interest bearing to the Mortgagors. Mortgagors will not claim any
credit on, or make any deduction from the Indebtedness by reason of the payment
of, any Imposition.



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     Mortgagors hereby assign to Mortgagee all rights of Mortgagors now or
hereafter arising in and to the refund of any Imposition and any interest
thereon. If at the time of receipt of any such refund by Mortgagee there exists
no Event of Default hereunder, then Mortgagee shall pay over the same to
Mortgagors promptly after demand; if there exists an Event of Default hereunder,
Mortgagee may apply said refund in reduction of the Indebtedness in whatever
order Mortgagee may elect.

         5. Tax Deposits. Mortgagors, Mortgagee and Fowler, Goedecke, Ellis &
O'Connor, Incorporated, as Escrow Agent, have entered into a certain Real Estate
Tax Escrow and Security Agreement of even date herewith, the terms of which
provide for the escrow and payments of money with respect to real estate taxes
(the "Tax Escrow Agreement"). Mortgagors covenant to perform their obligations
under the Tax Escrow Agreement, and Mortgagee hereby agrees that such
performance shall satisfy Mortgagors' obligations under this Mortgage with
respect to real estate taxes. In the event that Mortgagors shall default beyond
applicable grace periods under the Tax Escrow Agreement, or the Tax Escrow
Agreement shall be terminated for any reason, or in the event that the Tax
Escrow Agreement becomes ineffective or otherwise unenforceable, then the
balance of the terms and conditions of this Section 5 shall be applicable and
control with respect to real estate taxes.

     Mortgagors shall deposit with Mortgagee or with an escrow agent selected by
Mortgagors and approved by Mortgagee (not to be unreasonably withheld or
delayed) pursuant to an


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escrow agreement reasonably acceptable to Mortgagee, on the first day of the
calendar month immediately following the date of this Mortgage and on the first
day of each calendar month thereafter (each of which dates is hereinafter called
the "monthly tax deposit date") until the payment in full of the Indebtedness, a
sum equal to one-twelfth of the real estate taxes, assessments and any other
Impositions which are required to be, or are customarily, paid with real estate
taxes or assessments (the "Qualified Impositions") to be levied, charged,
assessed or imposed upon or for the Security within one year after said monthly
tax deposit date. If on any monthly tax deposit date the amount of Qualified
Impositions to be levied, charged, assessed or imposed within the ensuing one
year period shall not be fixed, such amount, for the purpose of computing the
deposit to be made by Mortgagors hereunder, shall be estimated by Mortgagee,
with appropriate adjustment when the amount of such Qualified Impositions is
fixed.

     The sums deposited by Mortgagors under this Section shall be held in an
interest bearing account with interest being retained by Mortgagee and free of
trust, except as otherwise provided in the grammatical paragraph next following
and except to the extent, if any, that applicable law shall otherwise require,
and applied in payment of such Qualified Impositions when due (subject to
Mortgagors' contest rights set forth above). Mortgagors shall give fifteen (15)
days prior written notice to Mortgagee in each instance when a Qualified
Imposition is due, specifying the Qualified Imposition to be paid and the amount
thereof, the place of payment and the last day on which the same


                                      -16-
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may be paid in order to be within the time limit specified in Section 4 hereof
entitled "Impositions". Mortgagee shall not be responsible for any acts of or
events affecting the escrow agent nor shall Mortgagee have any obligation or
liability to Mortgagors if a different depository, or a different account with
the selected escrow agent, would or might pay a greater return on invested
funds.

     Notwithstanding the foregoing provision, so long as Mortgagors collectively
hold title to and control the Security, Impositions are paid in full when due
and there exists no uncured default under the Loan Documents, notice of which
has been given by Mortgagee to Mortgagors, the interest earned by such escrows,
less reasonable escrow costs, will be paid to Mortgagors on each monthly tax
deposit date; provided, however, that interest shall be paid only if the escrow
account is held by a mutually agreed escrow agent and not by Mortgagee itself.

     If for any reason the sums on deposit with Mortgagee or escrow agent under
this Section shall not be sufficient to pay a Qualified Imposition within the
time specified in Section 4 hereof, then Mortgagors shall, within ten (10) days
after demand by Mortgagee, deposit sufficient sums so that Mortgagee may pay
such Qualified Imposition in full, together with any penalty and interest
thereon, subject to Mortgagors' contest rights set forth above. Mortgagee may
change its estimate of Qualified Impositions for any period, on the basis of a
change in an assessment or tax rate or on the basis of a prior miscalculation or
for any other bona fide reason communicated by Mortgagee to


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Mortgagors, in which event Mortgagors shall deposit with Mortgagee or escrow
agent within ten (10) days after demand the amount of any excess of the deposits
which would theretofore have been payable under the revised estimate over the
sums actually deposited.

     If any Qualified Imposition shall be levied, charged, assessed or imposed
upon or for the Security, or any portion thereof, and if such Qualified
Imposition shall also be a levy, charge, assessment or imposition upon or for
any other premises not covered by the lien of this Mortgage, then the
computation of the amounts to be deposited under this Section shall be based
upon the entire amount of such Qualified Imposition and Mortgagors shall not
have the right to apportion any deposit with respect to such Qualified
Imposition.

     Upon an assignment of this Mortgage, Mortgagee shall have the right to
arrange to transfer all amounts deposited and still in its possession to the
assignee and, provided that the assignee assumes the obligations of Mortgagee
with respect to such amounts deposited, Mortgagee shall thereupon be completely
released from all liability with respect to such deposit and Mortgagors and the
owner of the Security shall look solely to the assignee or transferee in
reference thereto.

     Upon the payment in full by Mortgagors of the entire Indebtedness, any sums
then held by Mortgagee (or escrow agent) under this Section shall be refunded to
Mortgagors.



                                      -18-
<PAGE>



     All amounts deposited shall be held by Mortgagee as additional security for
the sums secured by this Mortgage, and each of Mortgagors hereby grants to
Mortgagee a security interest in such sums, and upon the occurrence of an Event
of Default hereunder, Mortgagee may, in its sole and absolute discretion, apply
said amounts to the payment of the Indebtedness in whatever order Mortgagee may
elect.

     Immediately upon receipt of such by any of the Mortgagors, such Mortgagor
shall deliver to Mortgagee copies of all notices, demands, claims, bills, and
receipts in relation to the Qualified Impositions.

     Notwithstanding the foregoing provisions, Mortgagee hereby waives the
requirement for deposits as to that portion of Qualified Impositions payable
directly to the governmental or other authority by tenants under the terms of
leases approved by Mortgagee, provided satisfactory proof of payment is promptly
furnished to Mortgagee.

     6. Change in Taxes. In the event that, by reason of changes in law or in
the application or interpretation thereof, any tax (other than general income
taxes and similar taxes based on income) shall be due or become due and payable
to the United States of America, the Commonwealth of Massachusetts or any
political subdivision thereof with respect to the execution and delivery or
recordation of this Mortgage or any other Loan Document or the interest of
Mortgagee in the Security, Mortgagors shall, subject to Mortgagors' contest
rights set forth in


                                      -19-
<PAGE>



Section 4 above, which shall be applicable hereto, mutatis mutandis, pay such
tax at the time and in the manner required by applicable law and Mortgagors
shall hold Mortgagee harmless and shall indemnify Mortgagee against any
liability of any nature whatsoever as a result of the imposition of any such
tax. Notwithstanding the foregoing, in the event that such tax shall be due or
become due and payable as aforesaid in an amount greater than $150,000 and if
Mortgagee shall require Mortgagors to make payment thereof or to indemnify
Mortgagee as aforesaid, Mortgagors shall have the right to prepay the
Indebtedness in full, without paying a prepayment fee. If one or more of the
Mortgagors are not permitted by law to make such payments, the Indebtedness
shall, at the option of Mortgagee, become due and payable upon one hundred
eighty (180) days notice without Mortgagors being obligated to pay a prepayment
fee. Notwithstanding the foregoing, Mortgagee shall not require Mortgagors to
pay such taxes or to indemnify Mortgagee as aforesaid, nor will Mortgagee
exercise its option to accelerate the Indebtedness pursuant to the preceding
sentence, unless it is the policy of Mortgagee to enforce such rights generally
(meaning that, over the course of numerous transactions, Mortgagee would more
often than not elect to enforce such rights) in connection with similar
commercial mortgage loans held by Mortgagee.

         7.       Insurance.  Mortgagors collectively shall, at all times
until the Indebtedness shall be paid in full, keep the Security
insured against loss or damage for its full replacement cost
(which cost shall be reset once a year at Mortgagee's option)
under policies of so-called All Risk Replacement Cost Insurance


                                      -20-
<PAGE>

with Agreed Amount Endorsement (including risks of war and nuclear explosion, if
available at commercially reasonable rates), and shall further provide flood
insurance (if the Security is situated in an area which is considered a flood
risk area by the federal government or any agency thereof), boiler and machinery
insurance, earthquake insurance (if available at commercially reasonable rates),
rent loss insurance in an amount sufficient to cover the total of all rents
accruing from the Security for a one (1) year period, comprehensive general
liability insurance in a minimum amount of One Million Dollars ($1,000,000), and
excess or umbrella liability of at least Five Million Dollars ($5,000,000), and
during any period of restoration, a policy or policies of builder's "all risk"
insurance in an amount not less than the full insurable value of the Security
against such risks as Mortgagee may reasonably request, and such other
appropriate insurance as Mortgagee may reasonably require from time to time, in
such amounts and with such companies as shall be reasonably approved by
Mortgagee with a Best's rating of A:X or better (except to the extent Mortgagee,
in its reasonable discretion, approves a lower Best's rating upon Mortgagors'
written request), and will deliver the original policy or policies of such
insurance (or certified duplicates thereof) to Mortgagee. Each such policy shall
provide that the same may not be cancelled or materially modified except upon
thirty (30) days prior written notice to Mortgagee, and shall otherwise be in
such form as shall be reasonably acceptable to Mortgagee, so that at all times
until the payment in full of the Indebtedness, Mortgagee shall have and hold the
said policy and policies (or certified duplicates thereof) as further collateral


                                      -21-
<PAGE>


for the payment of all Indebtedness. Each liability policy shall name Mortgagee
as an "additional insured"; and each other policy required to be maintained
hereunder (other than rent loss insurance) shall name Mortgagee as "loss payee"
and provide that all proceeds shall be payable to Mortgagee and that no act or
thing done by Mortgagors shall invalidate the policy as against Mortgagee, and
shall be endorsed with standard non-contributory mortgagee clauses and lender's
loss payee endorsements in favor of and in form reasonably acceptable to
Mortgagee. If Mortgagors shall fail to obtain any such policy or policies
required by Mortgagee, or shall fail to deliver the same (or certified
duplicates thereof) to Mortgagee, then Mortgagee may, after ten (10) days notice
to Mortgagors (or such shorter notice period as shall be appropriate if the
policy is about to expire), obtain such insurance and pay the premium or
premiums therefor, in which event Mortgagors shall, on demand of Mortgagee,
repay such premium or premiums to Mortgagee and such repayment shall be secured
by the lien of this Mortgage. Notwithstanding the foregoing, provided that such
policies providing for such coverages are in fact in effect (as evidenced by
certificates thereof delivered by Mortgagors to Mortgagee), and that Mortgagors
have paid the premiums therefor, Mortgagors shall not be required to deliver any
such insurance policy (or a certified duplicate thereof) to Mortgagee until the
policy (or a certified duplicate thereof) is delivered to Mortgagors by the
insurer. Mortgagors each covenant to exercise reasonable efforts to secure
delivery of such policies from the insurer promptly after the policy has been
underwritten and approved by the insurer. If Mortgagors fail to maintain the
level of insurance required under


                                      -22-
<PAGE>



this Mortgage with regard to their Respective Security (defined hereinbelow),
then Mortgagors shall indemnify Mortgagee to the extent that a casualty occurs
with regard to their Respective Security and insurance proceeds would have been
available had such insurance been maintained.

     For purposes of this Mortgage and the other Loan Documents, the term
"Respective Security" shall mean (i) with regard to BPLP, the BPLP Parcels and
all of the corresponding Real Property and Personal Property pertaining thereto,
(ii) with regard to Wellesley I, the Wellesley I Parcels and all of the
corresponding Real Property and Personal Property pertaining thereto, and (iii)
with regard to Wellesley II, the Wellesley II Parcel and all of the
corresponding Real Property and Personal Property pertaining thereto.

     Mortgagors shall promptly provide to Mortgagee copies of any and all
material notices (including notice of non-renewal and policy amendments),
claims, and demands which Mortgagors receive from insurers of the Security.

     Mortgagors hereby assign to Mortgagee all rights of Mortgagors in and to
any unearned premiums on any insurance policy required to be furnished by
Mortgagors, which assignment may be exercised by Mortgagee at any time an Event
of Default exists hereunder.



                                      -23-
<PAGE>


     8. Insurance/Condemnation Proceeds. Mortgagors hereby assign to Mortgagee
all proceeds of any insurance or condemnation awards which Mortgagors may be
entitled to receive for loss or damage to, or a taking of, the Security. In the
event of loss or damage to, or a taking of, the Security, the proceeds of said
insurance or condemnation award shall be payable to Mortgagee alone and each of
the Mortgagors hereby authorizes and directs any affected insurance company or
government agency to make payment of the insurance proceeds or condemnation
awards directly to Mortgagee; provided, however, if such proceeds or awards do
not exceed Three Hundred Thousand Dollars ($300,000), they shall be paid to
Mortgagors instead of Mortgagee for application by Mortgagors to the costs of
repair or restoration provided that there exists no uncured monetary default
under the Loan Documents and no uncured non-monetary default of which notice has
been given by Mortgagee to Mortgagors under the Loan Documents. In the event
that any such insurance proceeds or condemnation awards in excess of Three
Hundred Thousand Dollars ($300,000) are paid directly to Mortgagors, Mortgagors
shall deliver such proceeds or awards to Mortgagee within five (5) days of
Mortgagors' receipt thereof. No such loss or damage shall itself reduce the
Indebtedness. Unless an Event of Default exists hereunder, Mortgagors shall have
the right, with Mortgagee's consent, which consent shall not be unreasonably
withheld or delayed, to adjust and compromise any loss or damage; provided,
however, that if such loss or damage does not exceed Three Hundred Thousand
Dollars ($300,000), and provided no Event of Default exists hereunder,
Mortgagors shall have the right to so adjust and compromise without Mortgagee's
consent. Subject to the


                                      -24-
<PAGE>


provisions of Sections 9, 10, and 11 hereof, such proceeds or awards shall be
applied first toward reimbursement of all reasonable costs and expenses of
Mortgagee in collecting said proceeds or awards, then toward payment of the
Indebtedness or any portion thereof then outstanding, in whatever order
Mortgagee may elect, or Mortgagee may, at its option, apply said insurance
proceeds or condemnation awards in whole or in part toward restoration of the
Security for which such insurance proceeds or condemnation awards shall have
been paid. Any insurance proceeds or condemnation awards received by Mortgagee
on account of a loss or damage to, or taking of, the Security shall, until the
same are applied by Mortgagee as aforesaid, be held by Mortgagee in an
interest-bearing account, with all interest and other income earned thereon to
accrue to Mortgagors' benefit (except as set forth in the next following
sentence of this Section 8); and such proceeds or awards shall be invested at
Mortgagors' direction in the investments permitted under the Tax Escrow
Agreement, unless an Event of Default exists hereunder, in which event Mortgagee
shall direct such investments. Notwithstanding the foregoing, interest on such
proceeds and awards only shall be payable if Mortgagee and Mortgagors make
arrangements for a mutually acceptable third party to hold such proceeds and
awards and to invest the same pursuant to an agreement reasonably acceptable to
Mortgagee; if Mortgagee itself holds such proceeds and awards, Mortgagee shall
have no obligation to pay interest thereon. The income earned in respect of such
proceeds or awards shall be added thereto, and shall be held and applied by
Mortgagee in the same manner as provided for herein with respect to the proceeds
or awards themselves.


                                      -25-
<PAGE>


     In the event of foreclosure of this Mortgage or other transfer of title to
the Security in lieu of foreclosure, all right, title, and interest of
Mortgagors in and to any insurance policy, or premiums or payments of proceeds
or awards in satisfaction of claims or any other rights thereunder then in
force, shall pass to the purchaser or grantee notwithstanding the amount of any
bid at such foreclosure sale. Nothing contained herein shall prevent the accrual
of interest as provided in the Note on any portion of the principal balance due
under the Note until such time as the insurance proceeds or condemnation awards
are actually received and applied to reduce the principal balance outstanding.

         9. Restoration Following Fire and Other Casualty or Condemnation. In
the event of damage to the Security by reason of fire or other hazard or
casualty, Mortgagors shall give prompt written notice thereof to Mortgagee and
(subject to the following provisions) shall proceed with reasonable diligence to
perform repair, replacement and/or rebuilding work (hereinafter referred to as
the "Work") to restore the Security to substantially its condition prior to such
damage in compliance in all material respects with all legal requirements,
provided that Mortgagee makes insurance proceeds available therefor. In the
event of a taking by power of eminent domain or conveyance in lieu thereof
("condemnation"), if restoration is feasible as reasonably determined by
Mortgagee, then Mortgagors (subject to the following provisions) shall proceed
with reasonable diligence to perform such restoration (also referred to as the
"Work"), provided that Mortgagee makes the condemnation awards available


                                      -26-
<PAGE>



therefor. Before commencing the Work, Mortgagors shall comply with the following
requirements if the cost of the Work exceeds Three Hundred Thousand Dollars
($300,000):

          a. Mortgagors shall furnish to Mortgagee complete plans and
specifications for the Work, for Mortgagee's approval, which approval shall not
be unreasonably withheld. Said plans and specifications shall bear the signed
approval thereof by an architect reasonably satisfactory to Mortgagee and shall
be accompanied by the architect's signed estimate, bearing the architect's seal,
of the entire cost of completing the Work.

          b. Mortgagors shall furnish to Mortgagee certified copies of all
permits and approvals required by law in connection with the commencement and
conduct of the Work.

          c. Mortgagors shall furnish to Mortgagee, prior to the commencement of
the Work, a surety bond for or guaranty of completion of and payment for the
Work, which bond or guaranty shall be in form satisfactory to Mortgagee and
shall be signed by a surety or sureties, or guarantor or guarantors, as the case
may be, who are reasonably acceptable to Mortgagee, and in an amount not less
than the architect's estimate of the entire cost of completing the Work, less
the amount of insurance proceeds or condemnation awards, if any, then held by
Mortgagee and which Mortgagee shall have elected or shall be required to apply
toward restoration of the Security as provided in Section 10 hereof.


                                      -27-
<PAGE>

     If the cost of the Work exceeds Three Hundred Thousand Dollars ($300,000),
Mortgagors shall not commence any of the Work until Mortgagors shall have
complied with the above requirements, and thereafter Mortgagors shall perform
the Work diligently (subject to delays caused by events of force majeure) and in
good faith substantially in accordance with the plans and specifications
referred to in subsection (a) above.

     If, as provided in Section 10 hereof, Mortgagee shall have elected or is
required to apply any insurance proceeds or condemnation awards toward repair or
restoration of the Security, then so long as the Work is being diligently
performed (subject to delays caused by events of force majeure) by Mortgagors in
accordance with the provisions of this Mortgage, Mortgagee shall disburse such
insurance proceeds or condemnation awards to Mortgagors from time to time during
the course of the Work in accordance with the following provisions which shall
be applicable if the cost of the Work exceeds $300,000:

          A. The Work shall be in the charge of an experienced construction
     manager reasonably satisfactory to Mortgagee with the consultation of an
     architect or engineer, and before Mortgagors commence any Work, Mortgagee
     shall have approved the plans and specifications for the Work to be
     submitted by Mortgagors, it being nevertheless understood that, to the
     extent feasible, said plans and specifications shall provide for such Work
     that, upon completion thereof, the items being repaired or restored shall
     be at least equal in value and general utility to


                                      -28-
<PAGE>

     their value and general utility prior to the damage, destruction or
     condemnation;

          B. Each request for payment shall not be made more often than at
     thirty (30) day intervals, on seven (7) business days prior notice to
     Mortgagee, and shall be accompanied by a certificate from an architect or
     engineer with respect to items (i) and (iv) and a certificate from
     Mortgagors with respect to items (ii), (iii), (v) and (vi), dated not more
     than ten (10) days prior to the application for withdrawal of funds,
     stating:

               (i) that, to the best of its knowledge and belief, based upon
          diligent performance under its contract with Mortgagors in accordance
          with generally accepted standards of professional knowledge and skill,
          all of the Work for which payment is being requested is in place
          (except for materials stored off-site with Mortgagee's consent, which
          shall not be unreasonably withheld or delayed) and has been completed
          substantially in compliance with the approved plans and specifications
          and all applicable legal requirements;

               (ii) that the sum then requested to be withdrawn has been paid by
          Mortgagors and/or is justly due to contractors, subcontractors,
          materialmen, engineers, architects or other persons (whose names and
          addresses shall be stated) who have rendered or furnished certain
          services or materials for the Work and giving a brief description of
          such services and materials and the


                                      -29-
<PAGE>


     principal subdivisions or categories thereof and the respective amounts so
     paid or due to each of said persons in respect thereof and stating the
     progress of the Work up to the date of said certificate;

               (iii) that the sum then requested to be withdrawn, plus all sums
          previously withdrawn, does not exceed the cost of the Work insofar as
          actually accomplished up to the date of such certificate and that the
          remainder of the monies held by Mortgagee will be sufficient to pay
          for the completion of the Work in full;

               (iv) that, to the best knowledge of such architect or engineer,
          the remainder of the moneys held by Mortgagee will be sufficient to
          pay in full for the completion of the Work;

               (v) that no part of the cost of the services and materials
          described in the foregoing paragraph (ii) of this Clause B has been or
          is being made the basis of the withdrawal of any funds in any previous
          or then pending application; and

               (vi) that, except for the amounts, if any, specified in the
          foregoing paragraph (ii) of this Clause B to be due for services or
          materials, there is no outstanding indebtedness known, after due
          inquiry, which is then due and payable for work, labor, services


                                      -30-
<PAGE>


          or materials in connection with the Work which, if unpaid, might
          become the basis of a vendor's, mechanic's, laborer's or materialman's
          statutory or other similar lien upon the Security or any part thereof.

          C. Mortgagors shall deliver to Mortgagee reasonably satisfactory
     evidence that the Security and every part thereof, and all materials and
     all property described in the certificate furnished pursuant to the
     foregoing Clause B, are free and clear of all mortgages, liens, charges or
     encumbrances, except (a) encumbrances, if any, securing indebtedness due to
     persons (whose names and addresses and the several amounts due them shall
     be stated) specified in said certificate furnished pursuant to the
     foregoing Clause B, which encumbrances will be discharged upon disbursement
     of the funds then being requested, and (b) this Mortgage and the other
     Permitted Encumbrances. Mortgagee shall accept as satisfactory evidence
     under this Clause C a certificate of a title insurance company acceptable
     to Mortgagee or an endorsement to Mortgagee's existing loan title policy
     insuring the lien of this Mortgage, dated as of the date of the making of
     the disbursement, confirming the foregoing.

          D. Prior to the final disbursement, if Mortgagee reasonably requests,
     Mortgagors shall deliver to Mortgagee a survey of the Security dated as of
     a date within ten (10) days prior to the making of such disbursement
     showing no encroachments other than those, if any, shown on the survey




                                      -31-
<PAGE>

delivered to Mortgagee contemporaneously with the execution and delivery of this
Mortgage or otherwise acceptable to Mortgagee.

          E. Prior to the first disbursement, Mortgagors shall deliver to
     Mortgagee, to Mortgagee's reasonable satisfaction, an opinion of counsel
     that the Security, if repaired, replaced and/or rebuilt in accordance with
     the approved plans and specifications, would comply with all applicable
     zoning, building, and similar land use laws, rules, and regulations.

          F. There exists no uncured monetary default under the Loan Documents
     and no uncured non-monetary default notice of which has been given by
     Mortgagee to Mortgagors under any of the Loan Documents.

          Mortgagee at its option may waive any of the foregoing requirements.

          Upon compliance by Mortgagors with the foregoing Clauses A, B, C, D, E
     and F (except for such requirements, if any, as Mortgagee at its option may
     have waived), Mortgagors shall, to the extent of the insurance proceeds or
     condemnation award, if any, which Mortgagee shall have elected or shall be
     required to apply to restoration of the Security, pay or cause to be paid
     to the persons named in the certificate furnished pursuant to the foregoing
     Clause B, the respective amounts stated in said certificate to be


                                      -32-
<PAGE>



     due them less a retainage amount of 10% of the total contract price prior
     to 50% completion of the Work or such other retainage (or without
     retainage) ("Retainage") as shall be provided for in the applicable
     contract(s) approved by Mortgagee, which approval shall not be unreasonably
     withheld; and Mortgagee shall pay to Mortgagors the amounts stated in said
     certificate to have been paid by Mortgagors less Retainage.

          Upon completion of the Work, if the cost thereof exceeds Three Hundred
     Thousand Dollars ($300,000), in addition to the requirements of the
     foregoing Clauses A, B, C, D, E and F, Mortgagors shall promptly deliver to
     Mortgagee:

          (a) A written certificate of the architect or engineer that the Work
     has been fully completed in a good and workmanlike manner substantially in
     accordance with the approved plans and specifications;

          (b) An endorsement to Mortgagee's title insurance policy reasonably
     acceptable to Mortgagee insuring the Security against mechanics' and
     materialmen's liens;

          (c) A certificate by Mortgagors in form and substance reasonably
     satisfactory to Mortgagee, listing all costs and expenses in connection
     with the completion of the Work and the amount paid by Mortgagors with
     respect to the Work; and



                                      -33-
<PAGE>


                  (d) A temporary certificate of occupancy and all other
         applicable certificates, licenses, consents and approvals issued by
         governmental agencies or authorities with respect to the Security and
         (if obtainable) by the appropriate Board of Fire Underwriters or other
         similar bodies acting in and for the locality in which the Security is
         situated, provided further that within thirty (30) days after
         completion of the Work, Mortgagors shall obtain and deliver to
         Mortgagee a permanent certificate of occupancy for the Security or
         affected portions thereof.

     Upon receipt of the foregoing items, Mortgagee shall pay any Retainage
still held by Mortgagee to Mortgagors.

     If upon completion of the Work there shall be insurance proceeds or
condemnation awards held by Mortgagee over and above the amounts withdrawn
pursuant to the foregoing provisions plus undisbursed Retainage, then, if an
Event of Default exists, Mortgagee may retain such proceeds or awards and apply
the same in reduction of the Indebtedness in whatever order Mortgagee may elect,
and if no Event of Default exists, Mortgagee shall pay over such proceeds or
awards to Mortgagors.

     10. Disposition of Condemnation or Insurance Proceeds. If such proceeds
exceed Three Hundred Thousand Dollars ($300,000), Mortgagee, in its absolute
discretion (except as hereinafter provided), may decide whether and to what
extent, if any, proceeds of insurance or condemnation will be made available to
Mortgagors for repair or restoration of the Security, but

                                      -34-

<PAGE>



Mortgagors shall effect such repair or restoration as set forth above provided
Mortgagee makes such proceeds available for that purpose. Notwithstanding the
foregoing, Mortgagee agrees to make insurance or condemnation proceeds available
to Mortgagors for repair or restoration provided:

     (i)  The damage to the Improvements on the Real Property or the value of
          the taking does not exceed sixty percent (60%) of the replacement cost
          thereof, and, in the case of a condemnation, the portion of the
          Security not taken by condemnation has not, in Mortgagee's reasonable
          opinion, been rendered economically nonviable by the taking;

     (ii) There exists no uncured non-monetary default of which notice has been
          given by Mortgagee to Mortgagors and no uncured monetary default under
          the Note or any other Loan Documents;

    (iii) Mortgagors can demonstrate to Mortgagee's satisfaction that
          Mortgagors have the financial ability (through rent insurance or
          otherwise) to make all scheduled payments when due under the Loan
          Documents during repair or restoration;

     (iv) In the case of a casualty, the damage to the Real Property can be
          fully restored at least two months prior to the Maturity Date;


                                      -35-
<PAGE>



     (v)  In the case of condemnation, sufficient parking remains, and the
          operation of the Security will not, in Mortgagee's reasonable opinion,
          be materially and adversely affected;

     (vi) The proceeds are released under the escrow/construction funding
          arrangements specified in Section 9 hereof;

    (vii) Annual income from leases in place and approved (or deemed approved)
          by Mortgagee (which will include, for purposes hereof, leases for
          which Mortgagee's approval is not required hereunder) that will
          survive restoration provide coverage of at least 1.40 times the annual
          debt service (interest and, if applicable, principal) on the Loan; and

   (viii) The Work will return the Improvements to substantially the size,
          design, and utility as existed immediately before the casualty.

          If Mortgagee elects not to, and is not required to, make the proceeds
available for repair or restoration, then such proceeds shall be applied to
reduce the Indebtedness in whatever order Mortgagee may elect. Any application
of such proceeds to the principal indebtedness evidenced by the Note shall be at
par and shall cause a pro rata reduction in payments of interest and, if
applicable, principal, under the Note; provided, however, that


                                      -36-
<PAGE>

if there exists an Event of Default, the prepayment fee as provided in the Note
shall also be due. Prepayment of the loan following Mortgagee's application to
principal reduction of insurance or condemnation proceeds shall be permitted
without payment of a prepayment fee, provided there then exists no Event of
Default under the Loan Documents and provided further that (i) such prepayment
must be made within one hundred eighty (180) days of Mortgagee's application to
principal reduction; (ii) Mortgagors keep Mortgagee informed of its progress in
seeking replacement financing; and (iii) Mortgagors provide Mortgagee with
thirty (30) days advance notice of prepayment.

     11. Fire and Other Casualty; Self-Help. Subject to delays caused by events
of force majeure: If within one hundred eighty (180) days after the occurrence
of any damage to the Security or the condemnation of any portion of the Security
in excess of Three Hundred Thousand Dollars ($300,000), Mortgagors shall not
have submitted to Mortgagee for Mortgagee's approval the plans and
specifications for the Work, or shall not have obtained or be diligently seeking
to obtain approval of such plans and specifications from all governmental
authorities whose approval is required, or if, after such plans and
specifications are approved by Mortgagee and all such governmental authorities,
Mortgagors shall fail to promptly commence such Work, or if thereafter
Mortgagors fail to perform the Work diligently or are delinquent in the payment
to mechanics, materialmen or others of the costs incurred in connection with the
Work (provided that Mortgagee shall have made proceeds available therefor), or,
if Mortgagors shall fail to complete the Work promptly, then, in


                                      -37-
<PAGE>

addition to all other rights herein set forth, and after giving Mortgagors
twenty (20) days written notice of the nonfulfillment of one or more of the
foregoing conditions and if such conditions remain uncured, Mortgagee, or,
following an Event of Default, any lawfully appointed receiver of the Security,
may at its option, perform or cause the Work to be performed, and may take such
other steps as it deems advisable to perform the Work, and may enter upon the
Security for any of the foregoing purposes, and Mortgagors hereby waive (to the
extent Mortgagors may lawfully do so) any claim against Mortgagee or such
receiver arising out of anything done by Mortgagee or such receiver pursuant to
this Section (other than claims arising by reason of the gross negligence or
willful misconduct of Mortgagee or such receiver) and Mortgagee may apply
insurance proceeds (without the need to fulfill the requirements of Section 9
hereof) to pay for restoration costs or to reimburse Mortgagee and/or such
receiver for all amounts expended or incurred by them, respectively, in
connection with the performance of the Work, and any excess costs incurred by
Mortgagee shall be paid by Mortgagors to Mortgagee upon demand with interest at
the Default Rate (hereinafter defined) from the date of demand and such payment
shall be secured by the lien of this Mortgage.

     12. Rent Insurance Proceeds. If there shall be no Event of Default under
the Loan Documents, then all rent insurance proceeds shall be paid directly to
Mortgagors. If there exists an Event of Default, then such rent insurance
proceeds shall be paid to Mortgagee and may be applied by Mortgagee, at
Mortgagee's


                                      -38-
<PAGE>

option, to the payment of the Indebtedness in whatever order Mortgagee may
elect.

     13. Intentionally Omitted.

     14. Repair; Alterations; Waste; Environmental. Mortgagors shall keep all of
the Security in good and substantial repair, subject to the provisions of
Section 9, to the extent applicable, and expressly agree that they will neither
permit nor commit any waste upon the Security, nor do any act or suffer or
permit any act to be done to diminish the value of the Security or whereby the
lien hereof may be impaired. Mortgagors shall comply in all material respects
with all zoning laws, building codes, subdivision laws, environmental laws, and
other laws, ordinances, rules and regulations made or promulgated by any
government or municipality, or by any agency thereof or by any other lawful
authority, which are now or may hereafter become applicable to the Security,
including but not limited to the Americans with Disabilities Act of 1990
("ADA"). Mortgagors shall use all reasonable efforts to cause tenants of the
Real Property to comply with their lease requirements regarding ADA. Without
limiting the foregoing, Mortgagors shall comply in all material respects (within
the time schedule set forth therein) with the ADA Compliance Plan, prepared by
Mortgagors, dated January 2, 1996, previously submitted to and approved by
Mortgagee. Mortgagors agree not to initiate or acquiesce in any zoning variance
or reclassification, without Mortgagee's prior written consent. Mortgagors shall
not construct any additional building or buildings or make any other material
improvements on the Land


                                      -39-
<PAGE>

nor alter, remove or demolish any building or other Improvements on the Land in
any material respect, without the prior written consent of Mortgagee (which
consent shall not be unreasonably withheld or delayed), except for (i) tenant
improvement work in accordance with leases approved (or deemed approved) by
Mortgagee or which Mortgagee is not required to approve pursuant to Section 22
of this Mortgage, and (ii) an expansion of the building located at 100 William
Street of up to 30,000 square feet subject to satisfaction of the following: (a)
there shall be in place throughout the construction period adequate insurance
(including builder's "all risk" insurance) naming Mortgagee as an additional
insured; (b) Mortgagors shall pay-off or bond or insure over all mechanics liens
and materialmens liens within one-hundred eighty (180) days of any filing
thereof; (c) at no time during the term of the Loan shall any subordinate
financings or lien exist with respect to the Security except those included
within the Permitted Encumbrances or approved by Mortgagee pursuant to the terms
hereof; (d) Mortgagors shall pay all of the reasonable fees and costs of
Mortgagee's representatives to inspect the expansion project no more than once
per month; (e) the expansion of the building is for office use and conforms with
the quality, appearance and design of the rest of the buildings in the Security;
(f) Beacon Properties Corporation or another affiliate of Mortgagors is the
construction manager for the expansion; and (g) Mortgagors shall provide
evidence to Mortgagee, in form and substance reasonably acceptable to Mortgagee,
that, following the expansion, the Wellesley II Parcel and the remainder of the
Security affected by the expansion will comply with all applicable legal
requirements, including, without limitation,


                                      -40-
<PAGE>

zoning, permitting and other land use restrictions. Mortgagors shall at all
times comply in all material respects with any restrictive covenants applicable
to the Security. Mortgagors shall repair or restore any building now or
hereafter under construction on the Security and complete the same within a
reasonable period of time, subject to provisions of Section 9, to the extent
applicable.

          If Mortgagors suffer or permit any Event of Default to exist under
this Section 14, or in the event of an emergency, Mortgagee, or a lawfully
appointed receiver of the Security, following an Event of Default, at
Mortgagee's option and from time to time, may perform, or cause to be performed,
any and all repairs and such other work as it deems necessary to bring the
Security into compliance with the provisions of this Section and may enter upon
the Security for any of the foregoing purposes, and each of the Mortgagors
hereby waives (to the extent Mortgagors may lawfully do so) any claim against
Mortgagee and/or such receiver arising out of such entry or out of any other act
carried out pursuant to this Section, except for claims arising out of the gross
negligence or willful misconduct of Mortgagee or such receiver. Mortgagors shall
upon demand repay to Mortgagee and such receiver, with interest at the Default
Rate, from the date of such demand, all amounts expended or incurred by them,
respectively, in connection with any action taken pursuant to this Section, and
such repayment shall be secured by the lien of this Mortgage.



                                      -41-
<PAGE>


                  Mortgagors represent and warrant that there are and covenant
that at all times (except in the event of repairs or restoration, where
temporary limitations may occur) there will be located on the Real Property
paved designated parking spaces for at least 1,889 cars, which number may be
subject to reduction (but not below requirements of any leases with respect to
the Security) in the event that legal requirements applicable to the Real
Property necessitate a reduction in such parking capacity and by the actual
number of parking spaces on any portion of the Real Property released pursuant
to Section 45 of this Mortgage (subject, however, to complying with the
requirements of subsections (ix) and (x) of said Section 45).

                  Mortgagors represent and warrant with regard to their
Respective Security that, except as disclosed to Mortgagee in the Environmental
Report (as defined and listed on Exhibit A to the Environmental Indemnification
Agreement, as defined in Section 15 hereof), Mortgagors have not used and will
not use and, to the best of Mortgagors' knowledge, no prior owner or current or
prior tenant, subtenant, or other occupant of all or any part of their
Respective Security has used or is using Hazardous Materials (hereinafter
defined) on, from or affecting the Security in any manner that violates the
Environmental Laws (hereinafter defined); that, to the best of Mortgagors'
knowledge, except as set forth in the Environmental Report, no Hazardous
Materials have been disposed of on or migrated onto their Respective Security in
violation of Environmental Laws and that Mortgagors will not permit or suffer
any such violation of the Environmental Laws.


                                      -42-
<PAGE>



          For purposes of this Mortgage, "Hazardous Materials" shall mean and
include those elements, materials, compounds, mixtures, wastes or substances
which are contained in the list of hazardous substances adopted by the United
States Environmental Protection Agency (the "EPA") or the Massachusetts
Department of Environmental Protection ("DEP") or any list of toxic pollutants
designated by Congress or the EPA or DEP, or which are defined as hazardous,
toxic, pollutant, infectious, flammable or radioactive by any of the
Environmental Laws and whether or not included in such lists, shall be deemed to
include all elements, materials, compounds, mixtures, wastes and substances
containing petroleum, asbestos, chlorinated hydrocarbons, or polychlorinated
biphenyls ("PCB's").

          For purposes of this Mortgage, "Environmental Laws" shall mean and
include any Federal, Massachusetts or local statute, law, ordinance, code, rule,
regulation, order, or decree (i) regulating or relating to protection of human
health or the environment insofar as the same concern the Disposal (hereinafter
defined) of any Hazardous Materials, as now or at any time hereafter in effect,
or (ii) regulating or imposing liability or standards of conduct concerning the
Disposal of Hazardous Materials, as now or at any time hereafter in effect, or
both, including, without limitation, the Massachusetts Oil and Hazardous
Material Release Prevention and Response Act, as amended, M.G.L. C. 21E
("Chapter 21E"), the Massachusetts Hazardous Waste Management Act, as amended,
M.G.L. C. 21C, the Federal Comprehensive Environmental Response, Compensation
and Liability Act, as amended, 42 U.S.C. SS.9601 et. seq. ("CERCLA"), the
Superfund Amendments and


                                      -43-
<PAGE>


Reauthorization Act, 42 U.S.C. SS.9601 et. seq., the Federal Oil Pollution
Act of 1990, 33 U.S.C. SS.2701, et. seq., the Federal Toxic Substances
Control Act, 15 U.S.C. SS.2601 et. seq., the Federal Resource Conservation
and Recovery Act, as amended, 42 U.S.C. SS.6901 et. seq., the Federal
Hazardous Materials Transportation Act, 49 U.S.C. SS.1801 et. seq., the
Federal Clean Air Act, 42 U.S.C. S.7401 et. seq., the Federal Water Pollution
Control Act, 33 U.S.C. S.1251 et. seq., the River and Harbors Act of 1899, 33
U.S.C. SS.401 et. seq., and all laws, statutes, rules, ordinances and
regulations of the EPA, or any other local, state or federal department, board,
or agency, or any other agency or governmental board or entity having
jurisdiction over the Security, as any of the foregoing have been, or are
hereafter from time to time, amended, reauthorized, replaced, supplemented or
superseded.

          Mortgagors individually and collectively represent and warrant with
regard to their Respective Security that, to the best of their individual and
collective knowledge, except as set forth in the Environmental Report, no
presence, release, spill, transportation, migration, generation, treatment,
processing, storage, use, or disposal of any Hazardous Materials has occurred or
is occurring on, in, under, above or emanating from any portion of their
Respective Security by any person or entity or other source, whether related or
unrelated to one or more of the Mortgagors, in violation of any Environmental
Law (collectively a "Disposal") and that Mortgagors will not permit or suffer
any such Disposal of Hazardous Materials on the Security or permit any lien
under Chapter 21E or CERCLA or any other Environmental Law to


                                      -44-
<PAGE>



attach to the Security or any portion thereof or interest therein. Mortgagors
individually and collectively represent and warrant with regard to their
Respective Security that, except to the extent disclosed in the Environmental
Report, they have not received any notice from the DEP (or its predecessor, the
Massachusetts Department of Environmental Quality Engineering), the EPA or any
other governmental agency or any tenant of their Respective Security with regard
to such Hazardous Materials and have received no notice that the environmental
and ecological condition of their Respective Security is in violation of any
Environmental Law.

          Mortgagors individually and collectively represent and warrant with
regard to their Respective Security that, to the best of their knowledge and
belief, except as disclosed in the Environmental Report, their Respective
Security does not contain any asbestos-containing material in friable form, and
there is no current airborne contamination of their Respective Security by
asbestos fiber.

          Mortgagors individually and collectively represent and warrant with
regard to their Respective Security that, except as set forth in the
Environmental Report, they have not received any notice that the soil, surface
water, or ground water of or on their Respective Security are not free from any
spills of Hazardous Materials, and have no knowledge of any such spill except as
set forth in the Environmental Report.



                                      -45-
<PAGE>


     Notwithstanding anything to the contrary contained in this Mortgage or the
Environmental Indemnification Agreement, Mortgagee acknowledges that during the
ordinary course of office building and parking area operations, there are some
Hazardous Materials that are being used and stored on the Real Property by
Mortgagors and Mortgagors' tenants. Mortgagors each hereby represent and warrant
to Mortgagee with regard to their Respective Security that, to the best of their
knowledge, (i) such Hazardous Materials have not been used or stored in
violation of Environmental Laws in any material respect, and (ii) such Hazardous
Materials are present in quantities which are not known to pose a health or
safety hazard to occupants, employees or visitors to the Real Property or to any
adjacent property; and Mortgagors further covenant and agree that no such
Hazardous Materials shall be allowed to be present on their Respective Security
other than such ordinary use and incidental storage of Hazardous Substances as
are reasonably and customarily necessary for the regular and ordinary operation
and maintenance of their Respective Security as a first-class office building(s)
and parking areas, and in all events in compliance with applicable Environmental
Laws.

          In the event that any investigation, site monitoring, containment,
clean-up, removal, restoration or other remedial work of any kind or nature (the
"Remedial Work") is required by any applicable Environmental Law, any judicial
order or by any governmental entity because of, or in connection with, the
current or future presence, suspected presence, release or suspected release of
a Hazardous Material in or about the air, soil, ground water, surface water or
soil vapor at, on, about, under or within


                                      -46-
<PAGE>


the Security (or any portion thereof), Mortgagors shall within thirty (30) days
after written demand for performance thereof by Mortgagee (or such shorter
period of time as may be required under any applicable Environmental Law, court
order or governmental direction), commence and thereafter diligently prosecute
to completion, all such required Remedial Work so as to restore the Security to
compliance with all applicable Environmental Laws, court orders and governmental
directions. All such Remedial Work shall be performed by contractors approved
(which approval shall not be unreasonably withheld or delayed) in advance by
Mortgagee, and under the supervision of a consulting engineer approved (which
approval shall not be unreasonably withheld or delayed) by Mortgagee. All costs
and expenses of such Remedial Work shall be paid by Mortgagors including,
without limitation, Mortgagee's reasonable attorneys' fees, paralegal fees and
costs incurred in connection with monitoring or review of such Remedial Work. In
the event Mortgagors shall fail to timely commence and thereafter prosecute to
completion such Remedial Work, and such failure continues for thirty (30) days
after notice by Mortgagee to Mortgagors (or such shorter period of time as may
be required under any applicable Environmental Law, court order or governmental
direction or by the exigencies of the situation), Mortgagee may, but shall not
be required to, cause such Remedial Work to be performed and all costs and
expenses thereof, or incurred in connection therewith, shall become part of the
Indebtedness.

          Each Mortgagor shall provide Mortgagee with prompt written notice (a)
upon such Mortgagor's becoming aware of any


                                      -47-
<PAGE>

alleged, suspected or actual Disposal of any Hazardous Materials upon, in,
under, or emanating from their Respective Security in violation of Environmental
Laws; (b) upon such Mortgagor's receipt of any notice from any federal, state,
municipal or other governmental agency or authority in connection with any
Hazardous Materials located upon, in, or under or emanating from their
Respective Security; and (c) upon such Mortgagor's obtaining knowledge of any
incurrence of expense by any governmental agency or authority in connection with
the assessment, containment or removal of any Hazardous Materials located upon,
in, or under or emanating from their Respective Security.

          Mortgagors hereby authorize Mortgagee and its agents and consultants
at any time and from time to time, upon reasonable advance notice to Mortgagors,
to enter upon the Security to conduct an environmental audit of the
Improvements, soils and ground water, including subsurface investigation, in the
event that Mortgagee has reason to believe that a Disposal of Hazardous
Materials in violation of any Environmental Laws has occurred or when a change
of or addition to the Environmental Laws makes inspection reasonable, the cost
of such audit to be added to the Indebtedness. Mortgagee shall provide
Mortgagors with an estimate of the cost of any such audit and shall conduct such
audit in a manner intended to minimize interference with the operations of the
Security.

          Mortgagors hereby agree to prepare and to submit to Mortgagee for its
approval (which approval shall not be unreasonably withheld or delayed), within
ninety (90) days of the date hereof,


                                      -48-
<PAGE>



an operations and maintenance plan regarding any asbestos presently situated on
the Real Property. Mortgagors shall comply in all material respects with the
terms and conditions of such plan(s), and shall not modify, amend, limit, delete
or reduce any practice or procedure set forth in such plan without obtaining
Mortgagee's prior written consent (which consent shall not be unreasonably
withheld or delayed).

     15. Environmental Indemnification. Mortgagors and BPLP, in its own capacity
(collectively, the "Indemnitors"), have entered into an Environmental
Indemnification Agreement of even date herewith in favor of Mortgagee (the
"Environmental Indemnification Agreement"). The performance of the duties and
obligations of the Indemnitors under the Environmental Indemnification Agreement
shall be part of the Indebtedness secured by this Mortgage. Mortgagors'
obligations under the Environmental Indemnification Agreement are hereby
incorporated into this Mortgage by reference. Mortgagee's rights and remedies
under the Environmental Indemnification Agreement are intended to be in addition
to and not in substitution for any rights and remedies Mortgagee may have under
this Mortgage or as may generally be available to Mortgagee at law or in equity.

     16. Independence of Security. Mortgagors shall not by act or omission
permit any building or other improvement on any premises not subject to the lien
of this Mortgage to rely on the Security or any part thereof or any interest
therein to fulfill any municipal or governmental requirement, and Mortgagors
hereby assign to Mortgagee any and all rights to give consent for all or


                                      -49-
<PAGE>



any portion of the Security or any interest therein to be so used. Similarly, no
part of the Security shall rely on any premises not subject to the lien of this
Mortgage or any interest therein to fulfill any governmental or municipal
requirement. Mortgagors shall not by act or omission impair the integrity of the
Real Property as separate lots for zoning and subdivision purposes (separate and
apart from each other as well as from any other parcel of real property), or as
one or more complete tax parcels separate and apart from all other premises. Any
act or omission by Mortgagors which would result in a violation of any of the
provisions of this Section shall be void.

     17. No Other Liens. Mortgagors shall not consent, agree to, or permit any
mortgage, lien, or security interest upon or affecting the Security or any part
thereof except as granted or permitted in this Mortgage and any other lien or
security interest granted to Mortgagee. Normal and customary equipment leases
and purchase money financing obtained to purchase new Personal Property, in
either case entered into in the ordinary course of Mortgagors' business, shall
not constitute a violation of the provisions of this Section 17.

          Mortgagors will, subject to Mortgagors' contest rights set forth in 
Section 4 above, which shall be applicable hereto, mutatis mutandis, promptly
pay and discharge any and all amounts which are now or hereafter become liens
against the Security whether or not superior to the lien hereof or to any
assignment of rents and leases given to Mortgagee.



                                      -50-
<PAGE>



          Wellesley I and Wellesley II will not, without the express prior 
written consent of Mortgagee, conduct any business or acquire any properties
except for business and properties relating to the Security. Wellesley I and
Wellesley II are and shall at all times while this Mortgage is in effect remain
single purpose entities, with their only business being the ownership and
operation of their Respective Security. Wellesley I and Wellesley II will not
incur any debt and will not guarantee the debt of any other person or party
except indebtedness incurred pursuant hereto and any other indebtedness incurred
by Mortgagors (or any of them) to obtain funds to invest in the Security.

         18. Management. During the term of the loan secured hereby, the
Security shall at all times be operated and managed by an entity controlled by
BPLP or an entity approved by Mortgagee under a written management agreement
approved in advance in writing by Mortgagee and reasonably acceptable to
Mortgagee in form and substance. Mortgagee hereby approves Beacon Property
Management, L.P. or Beacon Property Management Corporation, each being an
affiliate of BPLP, as management agent for the Security. No change in such
management (other than substitution of Beacon Property Management, L.P. for
Beacon Property Management Corporation, or visa versa) shall be made without the
prior written approval of Mortgagee, and any attempted change in management
without Mortgagee's consent shall be void. Mortgagee's approval of the
management of the Security and the terms of any management agreement shall not
be unreasonably withheld, conditioned or delayed. Any manager must have the
expertise, competence and capacity to manage first-class facilities such as


                                      -51-
<PAGE>


the Real Property and have had actual experience managing either at least (i)
One Million (1,000,000) square feet of similar office building space in the
greater Boston area, or (ii) Two Million (2,000,000) square feet of similar
office building space in the United States. Each management agreement relating
to the Security (a) may not be modified or amended in any material respect and
any successor agreement may not be entered into or any management company
appointed (other than as permitted above) without Mortgagee's prior written
approval; and (b) must be unconditionally subordinate by its terms to the lien
of this Mortgage and terminable upon foreclosure of this Mortgage (or a deed in
lieu of foreclosure of this Mortgage) without termination fee or penalty or
other similar charge.

     19. Ground Lease. Mortgagors hereby represent and warrant to Mortgagee that
there exist no ground leases relating to or executed in connection with the
Security.

     20. Sidewalks, Municipal Charges. Mortgagors will promptly pay and
discharge any and all license fees and similar charges, with penalties and
interest thereon, which may be imposed by the municipality in which the Security
is situated, for the use of vaults, chutes, areas and other space beyond the lot
line and under or abutting the public sidewalks in front of or adjoining the
Security, and Mortgagors will promptly cure any violation of law and comply with
any order of such municipality respecting the repair, replacement or condition
of the sidewalk or curb in front of or adjoining the Security, and in default
thereof Mortgagee may, upon thirty (30) days notice to Mortgagors (or such
shorter


                                      -52-
<PAGE>


notice period as may be required in order to comply with legal requirements),
pay any and all such license fees or similar charges, with penalties and
interest thereon, and the charges of the municipality for such repair or
replacement, and any amount so paid or advanced by Mortgagee and all costs and
expenses incurred in connection therewith (including, without limitation,
attorneys' fees), with interest thereon at the Default Rate from the date of
demand, shall be a demand obligation of Mortgagors to Mortgagee, and, to the
extent permitted by law, shall be added to the Indebtedness and shall be secured
by the lien of this Mortgage. The provisions of this Section 20 are subject to
Mortgagors' contest rights set forth in Section 4 above, which shall be
applicable hereto, mutatis mutandis.

     21. Assignment of Rents and Leases. As further security for the payment of
the Indebtedness, Mortgagors hereby presently, irrevocably, absolutely and
unconditionally transfer, assign and set over unto Mortgagee all of their
individual and collective right, title and interest in and to all present and
future leases, lease termination agreements, license agreements, concession
agreements, parking management agreements and other occupancy agreements of any
nature, oral or written, of the Land and space in the Improvements, together
with all modifications, supplements, extensions, renewals and replacements
thereof now existing or hereafter made, and also together with the rights to sue
for, collect and receive all rents, prepaid rents, additional rents, royalties,
security deposits, damages payable upon default by tenant, or other sums in any
of said leases provided to be paid to the lessor thereunder, profits, income,
license fees, concession


                                      -53-
<PAGE>



fees and issues of the Security (collectively, "Rents"), to be applied by
Mortgagee in payment of the Indebtedness and also together with any and all
guaranties of the obligations of the tenants thereunder and the rights of
Mortgagors to receive, hold and apply all bonds and security in all of said
leases provided to be furnished to the lessor thereunder, and also together with
the rights of Mortgagors to enforce any and all of the agreements, terms,
covenants and conditions in all of said leases provided and to give notices
thereunder. Provided, however, that until an Event of Default occurs hereunder,
Mortgagors shall have a revocable license to collect the Rents and to exercise
and enjoy all of the aforesaid rights, privileges and benefits. Mortgagee may
receive and collect the Rents personally or through a receiver upon the
occurrence of an Event of Default, and during the pendency of any foreclosure
proceeding and during any redemption period. Upon the occurrence of an Event of
Default, Mortgagors agree to consent to a receiver if this is believed necessary
or desirable by Mortgagee to enforce its rights under this Section.
Notwithstanding anything contained herein to the contrary, if all outstanding
Events of Default are subsequently cured or waived prior to Acceleration of
Maturity (as defined in the Note), then Mortgagors automatically shall have the
same revocable license to collect the Rents and enjoy all of the aforesaid
rights, privileges, and benefits.

          Mortgagors shall not otherwise assign or pledge, or contract,
expressly or by implication, to assign or pledge, any lease of the Land or space
in the Improvements or the rights to sue for, collect and receive any Rents, or
the rights to receive,


                                      -54-
<PAGE>


hold and apply any bonds and security in any of said leases provided to be
furnished to the lessor thereunder, or the rights to enforce any of the
agreements, terms, covenants or conditions of said leases or to give notices
thereunder, unless in each instance the written consent thereto of Mortgagee be
first obtained.

          Nothing in this Mortgage shall be construed to obligate Mortgagee,
expressly or by implication, to perform any of the covenants of Mortgagors as
lessor under any of the leases hereinabove assigned or to pay any sum of money
or damages therein provided to be paid by the lessor.

          If, notwithstanding the occurrence of an Event of Default, Mortgagee
shall from time to time suffer or permit Mortgagors to sue for, collect or
receive any Rents, or to receive, hold or apply any bonds or security under any
of the leases hereinabove assigned, or to enforce any of the agreements, terms,
covenants or conditions thereunder or to give notices under said leases, after
the occurrence of an Event of Default, neither such sufferance nor permission
shall constitute a waiver or relinquishment by Mortgagee of the rights hereunder
and hereby assigned to Mortgagee with respect to any subsequent Rents, or with
respect to any subsequent receipt, holding or application of bonds or security
or any subsequent enforcement of such agreements, terms, covenants or conditions
or any subsequent notices; provided, however, notwithstanding the foregoing, it
is agreed by Mortgagee that if all outstanding Events of Default are cured or
waived prior to Acceleration of Maturity, then Mortgagors


                                      -55-
<PAGE>

automatically shall have the same revocable license to collect the Rents and to
otherwise deal with the leases as aforesaid.

     22. Future Leases. Except as provided hereinbelow, Mortgagors will not
hereafter make any lease to any tenant or amend, modify, terminate (except for
termination for default by the tenant and then only if the Real Property is
still owned by Wellesley I, Wellesley II and/or BPLP and no Event of Default
exists hereunder), accept surrender of, renew or extend any lease (other than a
renewal or extension to which a tenant is entitled under the terms of an
existing lease or contained in a lease that is subsequently approved or deemed
approved by Mortgagee), affecting the Security unless Mortgagee shall first
consent thereto in writing, which consent shall not be unreasonably withheld.

     Notwithstanding anything to the contrary contained herein, the aforesaid
approval requirements shall not apply with respect to (i) leases or amendments
to leases covering in each instance no more than 15,000 square feet of net
rentable area on the Real Property, or (ii) non-default lease terminations
unapproved by Mortgagee with respect to leases covering in each instance no more
than 15,000 square feet of net rentable area and aggregating not more than
45,000 net rentable square feet per calendar year. A lease termination incident
to relocation of tenants to other space within the Real Property shall not count
toward said 45,000 net rentable square feet per calendar year, except that any
net loss in occupied space between the old space and the new space shall be
counted. Further, if a terminated tenant is replaced with other



                                      -56-
<PAGE>

tenant(s) in substantially the same premises within sixty (60) days of
termination, such termination shall not count toward said 45,000 net rentable
square feet per calendar year if, and only if, in Mortgagors' good faith
judgment, the economic condition of the Real Property, after giving effect to
said particular replacement, remains the same or better than the prior
situation; provided, however, that any net loss in occupied space between the
terminated tenant and the new tenant(s) shall be counted.

     In addition, with respect to any new lease, amendment to lease or a
non-default lease termination as described in the immediately preceding
paragraph, all of the following conditions must be met:

          (a) The Mortgagor which is the landlord furnishes Mortgagee with
     certified copies of all such leases or amendments or terminations promptly
     following the execution of same by all the parties thereto, together with a
     detailed written breakdown of any and all costs to be incurred in
     connection therewith;

          (b) The Security must continue to be owned collectively by Wellesley
     I, Wellesley II and/or BPLP;

          (c) Mortgagors shall not be in default under the Note, this Mortgage
     or any other Loan Document beyond any applicable grace or cure period;



                                      -57-
<PAGE>


          (d) All such leases or amendments or terminations must be entered into
     in the ordinary course of business, and all such leases or amendments must
     be (i) prepared and executed on the standard lease or amendment form
     approved by Mortgagee, and (ii) consistent with such approved lease or
     amendment form, except that minor and customary changes which do not
     materially affect the value of the lease or the protections and assurances
     granted to Mortgagee thereunder may be made;

          (e) Any such lease or amendment or termination must be with a bona
     fide arms-length third-party tenant (unaffiliated with Mortgagors) and
     negotiated in good faith;

          (f) No such lease or amendment shall provide an ownership interest in
     the Security to the tenant; and

          (g) Any such lease or amendment must comply with the New Lease and
     Amendment Requisites (defined hereinbelow).

     In circumstances where Mortgagee's prior consent is required to a lease,
lease amendment, termination or other leasing matter, Mortgagee's consent shall
be deemed to have been given unless, within ten (10) business days after
Mortgagee receives copies of the proposed lease, amendment or termination in
final form, together with the written breakdown of costs as required in clause
(a) above (or as to other matters, after Mortgagee's receipt of Mortgagors'
request for approval, together with supporting documentation or information, as
appropriate), Mortgagee advises


                                      -58-
<PAGE>


Mortgagors of its disapproval and the grounds therefor. Mortgagors' request for
Mortgagee's approval under this Section 22 must be accompanied by a notice from
the Mortgagor which is the landlord highlighted in bold-faced capital letters
stating that Mortgagee's failure to respond within ten (10) business days will
result in Mortgagee's deemed approval as aforesaid. If Mortgagors fail to
provide such notice to Mortgagee, then the automatic approval provision provided
hereinabove shall not be applicable.

          In addition to the foregoing, Mortgagors promptly shall furnish to
Mortgagee (i) progress drafts and letters of intent, if any, concerning proposed
leases, and (ii) copies of all default and/or termination notices which
Mortgagors give to or receive from tenants.

          All future leases must expressly state that they are subordinate to
the lien of this Mortgage unless Mortgagee otherwise specifies. Unless otherwise
approved by Mortgagee, each future lease and each future amendment to leases
existing on the date hereof which extends the term by more than one (1) year
(other than pursuant to an extension or renewal option existing as of the date
hereof) must contain provisions that (i) upon notice to tenant by Mortgagee, the
lease shall become superior to the lien of the Mortgage, (ii) the tenant shall
attorn to any purchaser of the Real Property upon foreclosure of this Mortgage,
as amended from time to time, or in the event that a deed is given in lieu of
such foreclosure, and (iii) the tenant shall, upon receipt of notice from
Mortgagee under the separate Assignment of Rents and Leases given by Mortgagors
in favor of Mortgagee of even


                                      -59-
<PAGE>


date herewith, commence paying its rents directly to Mortgagee (collectively
herein referred to as the "New Lease and Amendment Requisites"). Notwithstanding
the foregoing, with respect to future amendments to leases existing on the date
hereof, the New Lease and Amendment Requisites need not be met if they are
already contained in the lease or the tenant shall have previously entered into
an SNDA (as hereinafter defined) with Mortgagee with respect to the same lease.

          Without limiting the foregoing, Mortgagee hereby reserves the right to
subordinate this Mortgage to any lease subsequently made by recording with the
Registry of Deeds in which this Mortgage is recorded a declaration to that
effect, executed by Mortgagee, which declaration once so recorded shall be
binding upon the tenant under such lease and its successors and assigns.
Mortgagee agrees, as to future leases and lease amendments, if requested to do
so by a tenant, to enter into a so-called subordination, non-disturbance and
attornment agreement ("SNDA"), on Mortgagee's standard form, with only such
changes as Mortgagee in its reasonable discretion agrees to (Mortgagee and
Mortgagors hereby agreeing with each other that they will each negotiate in good
faith with respect to changes to Mortgagee's standard form reasonably requested
by tenants), provided that Mortgagee shall have approved the lease or amendment
with such tenant.

          Mortgagors will furnish to Mortgagee a true and complete copy of each
lease, amendment, modification, extension, termination, or renewal of lease,
hereafter made by Mortgagors with respect to the Land or space in the Security,
within ten (10)


                                      -60-
<PAGE>


days after delivery of each such lease, amendment, modification, extension,
termination, or renewal by the parties thereto. After a tenant takes occupancy,
Mortgagors shall also furnish to Mortgagee a true and complete copy of a letter
agreement signed by such tenant confirming the commencement date and expiration
date of its lease, within ten (10) days after execution and delivery thereof by
such tenant and Mortgagors.

          Mortgagors will from time to time upon demand of Mortgagee, confirm in
writing the assignment to Mortgagee of any or all leases of the Land and space
in the Improvements, and such written confirmation shall be in substantially the
same form as the Assignment of Rents and Leases of even date herewith given by
Mortgagors to Mortgagee and as shall be necessary to make the same recordable.

          If Mortgagors receive an early termination fee from a tenant in excess
of $500,000 in connection with a lease termination agreement, then Mortgagors
shall deposit the entire fee into an interest-bearing escrow account to be
established with a mutually satisfactory escrow agent under a mutually
satisfactory escrow agreement, such escrowed funds to be released to Mortgagors
(a) to pay for leasing-related costs (e.g., tenant improvements, leasing
commissions, space planning, legal-leasing costs, and the like) and other
capital improvements, and (b) to the extent not used under (a) above, to
reimburse Mortgagors ratably on a monthly basis for the lost rent from the
terminated lease. In addition to the foregoing, if in any calendar year
cumulative termination fees


                                      -61-
<PAGE>

exceed $500,000, Mortgagors shall deposit those fees in excess of $500,000 into
an interest-bearing escrow account described above.

     23. Mortgagors' Obligations as Lessor. (a) Mortgagors shall, at Mortgagors'
cost and expense, perform in all material respects the obligations on the part
of the lessor to be performed pursuant to the terms of each and every lease or
letting, written or oral, now or hereafter made with respect to the Security or
any part or parts thereof, and shall not suffer or permit to exist any default
(beyond applicable notice and grace periods under said lease) in such
performance on the part of such lessor or permit any event to occur and continue
beyond the expiration of applicable notice and grace periods under the lease
which would give the tenant under any such lease the right to terminate the same
or to offset rent.

     (b) Mortgagors shall give Mortgagee immediate notice of the receipt by
Mortgagors of any notice of default from the tenant or its successors or assigns
under a lease, and Mortgagors shall furnish to Mortgagee promptly any and all
information which Mortgagee may request concerning the performance and
observance of all material covenants, agreements and conditions contained in the
leases by the lessor thereunder to be kept, observed and performed and
concerning the compliance with all terms and conditions of the leases.
Mortgagors hereby authorize Mortgagee and its representatives, upon reasonable
advance notice, to make investigations and examinations concerning such
performance, observance and compliance, and Mortgagors, upon request, shall
promptly deposit with Mortgagee any and all documentary evidence


                                      -62-
<PAGE>


relating to such performance, observance and compliance and copies of any and
all notices, communications, plans, specifications or other instruments or
documents received or given by Mortgagors in any way relating to or affecting
the leases which may concern or affect the estate of the lessor or the tenant in
or under the leases or in the premises thereby demised.

     (c) In the event of any failure by Mortgagors to keep, observe or perform
any covenant, agreement or condition contained in the leases or to comply with
the terms and conditions of the leases, which continues beyond the applicable
notice and grace period contained in the lease, any performance, observance or
compliance by Mortgagee pursuant to this Mortgage on behalf of Mortgagors shall
not remove or waive, as between Mortgagors and Mortgagee, the corresponding
Event of Default under the terms of this Mortgage.

     24. Leases; Foreclosure. Any proceedings or other steps taken by Mortgagee
to foreclose this Mortgage, or otherwise to protect the interests of Mortgagee
hereunder, shall not operate to terminate the rights of any present or future
tenant of space in the Improvements, notwithstanding that said rights may be
subject and subordinate to the lien of this Mortgage, unless (subject to the
terms of any SNDA now or hereafter executed by and between Mortgagee and a
particular tenant) Mortgagee specifically elects otherwise in the case of any
particular tenant. The failure to make any such tenant a defendant in any such
foreclosure proceeding and to foreclose such tenant's rights will not be
asserted by Mortgagors or any other defendant in such foreclosure


                                      -63-
<PAGE>



proceeding as a defense to any proceeding instituted by Mortgagee to foreclose
this Mortgage or otherwise protect the interests of Mortgagee hereunder.

     25. [Intentionally Omitted]

     26. Events of Default. Each of the following shall constitute an "Event of
Default" hereunder and shall entitle the Mortgagee to exercise its remedies
hereunder and under any of the other Loan Documents or as otherwise provided by
law:

          (a) (i) Any payment of any installment of principal or interest due
     under the Note, or payment of any escrow deposits due under any of the Loan
     Documents, is not received by Mortgagee within five (5) business days
     following the date when such payment was due, (ii) any failure to pay the
     outstanding Principal Indebtedness (as defined in the Note) on the Maturity
     Date or when the maturity of the Note is accelerated in accordance with the
     terms of the Note, this Mortgage or any other Loan Document, or (iii) any
     failure in the performance of any payment obligation of Mortgagors under
     this Mortgage or under any other Loan Document, other than the obligations
     to make payments as described in clauses (i) and (ii) above, and such
     failure continues uncured for a period of ten (10) business days after
     Mortgagee gives written notice of such failure to Mortgagors;

          (b) If there shall be a failure by Mortgagors to perform any duty of a
     non-monetary nature under any of the


                                      -64-
<PAGE>



     Loan Documents, which failure to perform is not cured within thirty (30)
     days after written notice from Mortgagee to Mortgagors of such failure to
     perform, except if such failure to perform is not susceptible of cure
     within such thirty (30) day period and Mortgagors commence to cure within
     such thirty (30) day period and thereafter diligently pursue such cure,
     then such cure period shall be extended for a reasonable period of time but
     in no event greater than one hundred twenty (120) days after such notice of
     failure to perform from Mortgagee to Mortgagors. Notwithstanding anything
     contained herein to the contrary, the notice and cure period provided under
     this clause (b) shall not be applicable to and shall not be in addition to
     any specific notice and cure or performance period provided under any other
     provision of this Section 26, and the specific notice and cure or
     performance period provided for in such provision of this Section 26 shall
     control, and a failure by Mortgagors to cure a default under such provision
     of this Section 26 within the applicable cure period shall be an Event of
     Default under this Mortgage;

          (c) if an "Event of Default" occurs under the Note or under any other
     Loan Document (as defined therein);

          (d) Any representation, warranty or statement of Mortgagors contained
     herein or in any of the other Loan Documents, including without limitation
     the Environmental Indemnification Agreement, which is actually known by
     Mortgagors to be untrue in any material respect as of the date when made;


                                      -65-
<PAGE>


          (e) Any representation, warranty, or statement of Mortgagors contained
     herein or in any of the other Loan Documents, including without limitation
     the Environmental Indemnification Agreement, which is not actually known by
     Mortgagors to be untrue in any material respect as of the date when made,
     but proves to be untrue in any material respect as of the date when made
     and remains untrue in any material respect for a period of thirty (30) days
     after Mortgagee gives Mortgagors a notice of default with respect thereto;
     provided, however, that if the nature of such representation, warranty or
     statement is such that the same cannot be made true in all material
     respects within such thirty (30) day period and any delay in Mortgagee's
     remedies would not (in Mortgagee's sole judgment) cause any material harm
     to Mortgagee or any of the Security, then the period required to make the
     same true in all material respects shall be extended, but in no event more
     than one hundred twenty (120) days in the aggregate, and such
     representation, warranty or statement shall not be deemed an Event of
     Default if Mortgagors shall within such thirty (30) day period commence to
     make the same true in all material respects and thereafter diligently
     prosecute such cure to completion within the time period allowed;

          (f) Any of Mortgagors, or any of Mortgagors' general partners, if
     Mortgagors are partnerships, or any of Mortgagors' controlling
     shareholders, if Mortgagors are corporations, shall (i) file a petition or
     petitions seeking relief under Title 11, United States Code, (ii) seek or


                                      -66-
<PAGE>

     consent to the appointment of a receiver or trustee for itself or
     themselves or for any of the Security, (iii) file a petition or petitions
     or initiate a proceeding or proceedings under the bankruptcy, insolvency,
     receivership, or similar laws of the United States, any state or any other
     jurisdiction, (iv) make a general assignment or assignments for the benefit
     of creditors, or (v) be generally unable to pay its or their debts as they
     mature;

          (g) A court shall enter an order, judgment or decree appointing,
     without the consent of one or more of the Mortgagors, a receiver or trustee
     for any of the Mortgagors or for any of the Security or approving a
     petition filed against any of the Mortgagors which seeks relief under the
     bankruptcy, insolvency, receivership or other similar laws of the United
     States, any state, or any other jurisdiction, and such order(s),
     judgment(s) or decree(s) shall remain in force, undischarged or unstayed,
     for ninety (90) days after the entry thereof;

          (h) Any of the Mortgagors shall voluntarily encumber the Land or the
     Improvements with any lien other than the lien of this Mortgage;

          (i) A Transfer not expressly permitted under the provisions of this
     Section 26(i) shall occur without the prior written consent of Mortgagee. A
     "Transfer" shall mean the sale, mortgage, encumbrance, pledge, assignment
     or hypothecation or other transfer (collectively,


                                      -67-
<PAGE>

     "Dispositions") (i) of legal or beneficial title to the Security or any
     portion thereof, excluding the Permitted Encumbrances, (ii) of any direct
     or indirect legal or beneficial interest in any partner or member of any
     Mortgagor, if such Mortgagor is a partnership, joint venture, syndication,
     limited liability company or other group, or (iii) of a controlling
     interest in the stock of any Mortgagor, if such Mortgagor is a corporation;
     the liquidation or dissolution of any Mortgagor or revocation or expiration
     of the charter of any Mortgagor shall also be deemed a Transfer.

          Notwithstanding anything to the contrary herein contained, an
involuntary lien or encumbrance constituting a "Transfer" within the meaning set
forth above shall not be deemed a Transfer hereunder (1) if any Mortgagor
removes, bonds or insures over the same to Mortgagee's reasonable satisfaction
within thirty (30) days after any Mortgagor becomes aware of such lien or
encumbrance and, in any event, prior to the same being foreclosed upon by the
party or parties claiming such lien or encumbrance, or (2) if such involuntary
lien or encumbrance is being contested by any Mortgagor in good faith and in
accordance with the provisions of Section 4 hereof, which shall be applicable to
such involuntary liens or encumbrances, mutatis mutandis.


          Notwithstanding anything to the contrary contained herein, Mortgagee
agrees that, so long as Wellesley I, Wellesley II and/or BPLP hold title to the
Security and there is no Event of


                                      -68-
<PAGE>


Default under the Loan Documents, the following Transfers shall be permitted
without Mortgagee's consent: (a) Transfers of interests in any Mortgagor to
Beacon Affiliates (as hereinafter defined) shall be permitted provided each
Mortgagor remains a "Domestic Entity" (i.e., a corporation, partnership or other
entity organized or formed under the laws of the United States of America or any
state thereof) domiciled in the United States of America; and (b) Beacon (as
hereinafter defined) (or Beacon's successors-in-interest as partners or members
of any Mortgagor, if applicable) shall be permitted to transfer from time to
time all or any part of its or their respective interests in any Mortgagor to a
non-affiliate, provided that (x) a Beacon Affiliate continues to own at least a
fifty percent (50%) interest in each Mortgagor and remains the managing general
partner or member of each Mortgagor, and (y) each Mortgagor remains a Domestic
Entity domiciled in the United States of America.

          For the purposes hereof, "Beacon" shall mean and include BPLP and/or
Beacon Properties Corporation, a Maryland corporation (the "Public REIT"); and a
"Beacon Affiliate" shall mean and include BPLP, the Public REIT and/or any other
entity which is at least 95% owned (directly or indirectly) by BPLP and/or the
Public REIT.

          Notwithstanding anything to the contrary contained herein, in no event
will any of the following Dispositions be prohibited or restricted under this
Mortgage: (x) Dispositions of stock interests in the Public REIT, and (y)
Dispositions of


                                      -69-
<PAGE>


limited partnership interests in BPLP so long as the Public REIT remains the
sole general partner of BPLP.

          Notwithstanding the provisions of this Section 26(i):

          A. Each Mortgagor shall have the right to transfer all or a portion of
the Security to a Beacon Affiliate or any other entity the ownership and control
of which is held by the same persons or entities which are permitted, under the
preceding provisions of this Section 26(i), to own and control Mortgagors (a
"Permitted Transferee"); provided that (I) no Event of Default exists under the
Loan Documents at the time of transfer; (II) the Permitted Transferee is a
Domestic Entity domiciled in the United States of America; (III) the Permitted
Transferee assumes the obligations of Mortgagors under the Loan Documents,
subject to the limitations on liability contained therein; and (IV) Mortgagors
shall pay for all of Mortgagee's reasonable costs and expenses associated with
the transfer, including, without limitation, attorneys' fees charged by
Mortgagee's staff counsel and outside special counsel. Upon such transfer, any
provision of this Mortgage which, by its terms, applies solely to "Mortgagors"
or "Wellesley I, Wellesley II and/or BPLP" shall also apply to such Permitted
Transferee. Following any such transfer, all the restrictions on transfers of
ownership interests in Mortgagors set forth in the preceding provisions of this
Section 26(i) shall apply to transfers of ownership interests in such Permitted
Transferee.



                                      -70-
<PAGE>


          B. Mortgagors shall also have the right to a one-time sale, transfer
or assignment in whole or in part of their interest in the Security to any party
of equal qualification and credit-worthiness provided:

          (I)  there is no monetary default or non-monetary default, notice of
               which has been given by Mortgagee to Mortgagors, under the Loan
               Documents at the time of transfer;

          (II) a property inspection by Mortgagee or Mortgagee's designee shows
               that all reasonably necessary maintenance on or damage or
               destruction to the Real Property has been completed or repaired;

         (III) the proposed transferee shall be a Domestic Entity or citizen of
               the United States of America domiciled in the United States of
               America;

          (IV) the proposed transferee shall be a Qualified Real Estate Investor
               (as hereinafter defined) which is a Domestic Entity or controlled
               by, or under common control with, a Qualified Real Estate
               Investor;

          (V)  the aggregate debt service coverage (based on Net Effective
               Rents, as hereinafter defined) on the Loan exceeds 1.50;


                                      -71-
<PAGE>

          (VI) the Qualified Real Estate Investor has specific related
               commercial real estate experience;

          (VII) the Qualified Real Estate Investor must own or manage a minimum
               of Two Million (2,000,000) square feet of Class A office space;

        (VIII) at least thirty (30) days prior to the transfer, Mortgagors
               must provide Mortgagee with all of the material provisions of
               such transfer including without limitation the proposed date of
               transfer, and the name, net worth, background and address of the
               proposed transferee and the purchase price;

          (IX) Mortgagors shall provide Mortgagee with such evidence as
               Mortgagee may reasonably require that the proposed transferee
               shall assume and fulfill each and every obligation of Mortgagors
               under the Loan Documents and such transfer shall not affect or
               impair Mortgagee's security and rights under the Loan Documents;

          (X)  a non-refundable fee in the amount of one percent (1%) of the
               outstanding Principal Indebtedness shall be paid to Mortgagee at
               the closing of the transfer in cash or certified check to be
               retained by Mortgagee in order to induce Mortgagee to allow the
               proposed transferee to assume the obligations of Mortgagors under
               the Loan Documents;


                                      -72-
<PAGE>


          (XI) the loan-to-value ratio of the Loan based on a then current
               appraisal obtained at Mortgagors' expense and acceptable to
               Mortgagee must not exceed 70%;

          (XII) Mortgagors shall pay for all of Mortgagee's reasonable costs and
               expenses associated with the transfer, including, without
               limitation, attorneys' fees charged by Mortgagee's staff counsel
               and outside special counsel; and

          (XIII) Any and all subordinate financing, whether or not previously
               consented to or approved by Mortgagee, which then encumbers all
               or any portion of the Security shall be completely discharged
               incident to the transfer.

          "Qualified Real Estate Investor" is defined as any reputable
corporation, partnership, joint venture, joint-stock company, trust or one or
more individuals which (x) shall have a minimum net worth of at least One
Hundred Fifty Million Dollars ($150,000,000), real estate assets of at least
Three Hundred Million Dollars ($300,000,000), and short-term liquid assets of at
least Ten Million Dollars ($10,000,000) and (y) if a foreign entity or
person(s), shall be represented by a domestic real estate advisor, and in any
case shall be free from any bankruptcy, reorganization or insolvency proceedings
or any criminal charges or proceedings in the United States of America or any
foreign country which would, in Mortgagee's reasonable judgment, raise a
material question as to the reputation of the investor or its


                                      -73-
<PAGE>



ability to own and to operate the Real Property and shall not have been, at the
time of transfer or in the past, an adverse party in any suit or proceeding
brought against or by Mortgagee. Mortgagee agrees to be reasonable in the review
of such qualifications.

          "Net Effective Rents" is defined as gross rent (including all rental
income for the twelve (12) month period immediately preceding the transfer)
minus operating expenses.

     27. Remedies Upon Default. Each of the Mortgagors expressly, absolutely and
unconditionally acknowledges and agrees that all and every portion of the
Security shall serve as collateral for all of the covenants, obligations and
agreements under this Mortgage and the other Loan Documents, and Mortgagee
shall, upon the occurrence of an Event of Default, be authorized to proceed
against all or any one or more portions of the Security singly, jointly,
concurrently or successively as Mortgagee may so decide in the exercise of
Mortgagee's sole and absolute discretion for the sole and exclusive benefit of
Mortgagee.

          Immediately upon the occurrence of any Event of Default, Mortgagee
shall have the option, in addition to and not in lieu of or substitution for all
other rights and remedies provided in this Mortgage or any other Loan Document
or provided by law or in equity, and is hereby authorized and empowered by
Mortgagors, to do any or all of the following:

          (a) Declare without notice the entire unpaid amount of the
Indebtedness immediately due and payable and, at Mortgagee's


                                      -74-
<PAGE>


option, (i) to bring suit therefor, or (ii) to bring suit for any delinquent
payment of or upon the Indebtedness, or (iii) to take any and all steps and
institute any and all other proceedings in law or in equity that Mortgagee deems
necessary to enforce payment of the Indebtedness and performance of other
obligations secured hereunder and to protect the lien of this Mortgage singly,
successively, jointly or concurrently with respect to all or any one or more
parts of the Security.

          (b) Exercise the STATUTORY POWER OF SALE and commence foreclosure
proceedings singly, successively, jointly or concurrently against all or any one
or more parts of the Security, in one parcel or in several parcels, through
judicial proceedings, by advertisement or as otherwise provided by law, at the
option of Mortgagee, pursuant to the statutes in such case made and provided,
and to singly, successively, jointly or concurrently sell all or any one or more
parts of the Security or to cause the same to be sold at public sale, and to
convey the same to the purchaser, in accordance with said statutes in a single
parcel or in several parcels at the option of Mortgagee. Mortgagors and
Mortgagee hereby acknowledge, covenant and agree that the Statutory Power of
Sale shall continue in existence and not be exhausted until Mortgagee, at its
election, has foreclosed upon all of the Security.

          (c) Proceed against all or any one or more parts of the Personal
Property singly, successively, jointly or concurrently in accordance with
Mortgagee's rights and remedies with respect to the Personal Property including
the right to sell all or any one


                                      -75-
<PAGE>

or more parts of the Personal Property together with all or any one or more
parts of the Real Property or separately and without regard to the remainder of
the Security in accordance with the Mortgagee's rights and remedies provided by
the Massachusetts Uniform Commercial Code as well as other rights and remedies
available at law or in equity.

          (d) Cause to be brought down to date a title examination and tax
histories of the Security, procure title insurance or title reports or, if
necessary, procure new abstracts and tax histories; procure an updated or
entirely new environmental audit of the Security including building, soil,
ground water and subsurface investigations; have the Improvements inspected by
an engineer or other qualified inspector and procure a building inspection
report; procure an MAI or other appraisal of the Security or any portion
thereof; enter upon the Security at any time and from time to time to accomplish
the foregoing and to show the Security to potential purchasers and potential
bidders at foreclosure sale; make available to potential purchasers and
potential bidders all information obtained pursuant to the foregoing and any
other information in the possession of Mortgagee regarding the Security.

          (e) Either by itself or by its agent to be appointed by it for that
purpose or by a receiver appointed by a court of competent jurisdiction, as a
matter of strict right, without notice and without regard to the adequacy or
value of any security for the Indebtedness or the solvency of any party bound
for its payment, to take possession of and to operate all or any one or


                                      -76-
<PAGE>

more parts of the Security, Mortgagors hereby waiving any right Mortgagors might
have to object to or oppose any such possession and, whether or not Mortgagee
has taken possession of the Security, to collect and apply the Rents, including
those past due and unpaid, after payment of all necessary charges and expenses,
in reduction of the Indebtedness. The receiver shall have all of the rights and
powers permitted under the laws of the Commonwealth of Massachusetts. Except for
damage caused by Mortgagee's gross negligence or willful misconduct, Mortgagors
hereby waive any claim Mortgagors may have against Mortgagee for mismanagement
of the Security during Mortgagee's operation of the Security under this
subparagraph or as mortgagee in actual possession under applicable statutes.

          (f) At its option without waiving any Event of Default, pay, perform
or observe any or all of Mortgagors' obligations under the Loan Documents, and
all payments made or costs or expenses incurred by Mortgagee in connection
therewith shall be secured hereby and shall be, upon demand, immediately repaid
by Mortgagors to Mortgagee with interest thereon at the Default Rate from the
date of demand. Mortgagee shall be the sole judge of the necessity for any such
actions and of the amounts to be paid. Mortgagee is hereby empowered to enter
and to authorize others to enter upon all or any one or more parts of the
Security for the purpose of performing or observing any such defaulted term,
covenant or condition without thereby becoming liable to Mortgagors or any
person in possession holding under Mortgagors, except for damage caused by
Mortgagee's gross negligence or willful misconduct.


                                      -77-
<PAGE>

          (g) Apply against the Indebtedness in such order as Mortgagee shall
determine any funds held for the benefit of Mortgagors in escrow by Mortgagee or
by any third-party escrow agent under any of the Loan Documents.

          Upon any foreclosure sale, Mortgagee may bid for and purchase all or
any one or more parts of the Security and shall be entitled to apply all or any
part of the Indebtedness as a credit to the purchase price. In the event of any
sale of all or any one or more parts of the Security by foreclosure, through
judicial proceedings, by advertisement or otherwise, the proceeds of any such
sale which are applied in accordance with this Mortgage shall be applied in the
order following to: (i) all sums reasonably expended or incurred by Mortgagee in
carrying out Mortgagors' obligations under this Mortgage and any other Loan
Documents, to the extent Mortgagee is authorized to do so under the terms of
this Mortgage or the other Loan Documents, together with interest thereon as
therein provided; (ii) all accrued and unpaid interest upon the Indebtedness;
(iii) the unpaid principal amount of the Indebtedness; (iv) Foreclosure Costs
(as hereinafter defined); and (v) the surplus, if any, to the person or persons
legally entitled thereto.

          Mortgagors will pay to Mortgagee upon demand all costs and expenses
incurred by Mortgagee upon the occurrence of an Event of Default in the exercise
of Mortgagee's rights and remedies under this Mortgage and the other Loan
Documents for collection of the Indebtedness, foreclosure on the Security or
otherwise, including without limitation title insurance fees and premiums,


                                      -78-
<PAGE>


environmental consultant's charges and appraisal, engineering and inspection
fees under Section 27(d), receiver's fees, costs and agent's compensation under
Section 27(e), auctioneer's fees and foreclosure sale advertising costs, any
deed excise tax stamps required to be affixed to the foreclosure deed and court
filing fees, together with attorneys' fees and costs which shall include without
limitation all attorneys' fees and costs incurred in connection with (A) the
exercise of Mortgagee's rights and remedies as aforesaid, (B) any negotiations,
other services and advice rendered regarding restructuring of the Indebtedness
prior to any foreclosure sale or deed-in-lieu of foreclosure, whether or not any
such restructuring or deed-in-lieu is actually accomplished, and (C) any
petition filed by or against any Mortgagor under Title 11, United States Code.
Any such amounts incurred by Mortgagee shall be secured hereby and shall be
immediately repaid by Mortgagors to Mortgagee upon demand with interest thereon
at the Default Rate, from the date of demand, all of such amounts together with
such interest being collectively referred to as "Foreclosure Costs."

          Mortgagors hereby agree that after a foreclosure sale, Mortgagors will
have no right to possess or remain upon the Security, Mortgagors acknowledging
Mortgagors' status as a trespasser in such circumstances.

          In the event of any acceleration of the Indebtedness pursuant to
paragraph (a) of this Section 27, Mortgagors shall pay to Mortgagee together
with the principal indebtedness and interest


                                      -79-
<PAGE>


thereon an amount equal to the prepayment fee provided for in the Note and such
fee shall be included as part of the Indebtedness.

          Failure to exercise any option to accelerate with respect to all or
any one or more parts of the Security during the existence of an Event of a
Default or other circumstance permitting the exercise of such option, shall not
constitute a waiver of the default or of the right to exercise such option at a
later time (so long as such Event of Default or other circumstance continues to
exist), or a waiver of the right to exercise such option in the event of any
other default or circumstance specified above.

     28. Acceleration Interest. In addition to any late payment charge which may
be due under the Note, Mortgagors shall pay interest on all sums due hereunder
at a rate (the "Default Rate") equal to the lesser of (i) the interest rate set
forth in the Note plus four percent (4%) per annum, or (ii) the maximum rate
permitted by law, from and after the first to occur of the following events: (A)
Mortgagee elects in writing to cause the acceleration of the Indebtedness; (B) a
petition under Title 11, United States Code, shall be filed by any Mortgagor or
if any Mortgagor shall seek or consent to the appointment of a receiver or
trustee for itself or for any of the Security, file a petition seeking relief
under the bankruptcy or other similar laws of the United States, any state or
any other jurisdiction, make a general assignment for the benefit of creditors,
or is generally unable to pay its debts as they become due; (C) a court shall
enter an order, judgment or decree appointing, with or without the consent

                                      -80-
<PAGE>



of any Mortgagor, a receiver or trustee for it or for any of the Security or
approving a petition filed against any Mortgagor which seeks relief under the
bankruptcy or other similar laws of the United States, any state or any other
jurisdiction, and any such order, judgment or decree shall remain in force,
undischarged or unstayed, ninety (90) days after it is entered; or (D) if all
sums due hereunder are not paid on the Maturity Date as set forth in the Note.

     29. Late Charge. In the event any sums due under the Note (exclusive of
principal due at maturity of the Note or by reason of the acceleration of the
Note), this Mortgage or any other Loan Document, are not paid by Mortgagors when
due, without regard to any cure or grace period, Mortgagors shall pay to
Mortgagee for the month during which such payment is not made when due and for
each month or fraction thereof that such sum remains unpaid, a late charge equal
to the lesser of four percent (4%) of such installment or the maximum amount
allowed by law, as the reasonable estimate by Mortgagee and Mortgagors of a fair
average compensation for the loss that may be sustained by Mortgagee due to the
failure of Mortgagors to make timely payments, and such amount shall be secured
hereby. Such late charge shall be paid without prejudice to the right of
Mortgagee to collect any other amounts provided to be paid or (if applicable) to
declare an Event of Default under this Mortgage or any other Loan Document.

     30. Waiver of Statutory Rights. Mortgagors agree, to the full extent
permitted by law, that upon an Event of Default hereunder, neither Mortgagors
nor anyone claiming through or under


                                      -81-
<PAGE>


Mortgagors will set up, claim, or seek to take advantage of any moratorium,
reinstatement, forbearance, appraisement, valuation, stay, homestead, extension,
exemption or (after a sale by foreclosure) redemption laws now or hereafter in
force, in order to prevent or hinder the enforcement or foreclosure of this
Mortgage, or the sale of the Security or the delivery of possession thereof
immediately after such sale to the purchaser at such sale, and Mortgagors, for
themselves and all who may at any time claim through or under any of them,
hereby waive to the full extent that they may lawfully do so, the benefit of all
such laws, and any and all rights to have the assets subject to the security
interest of this Mortgage marshalled upon any foreclosure or sale under the
power granted herein.

         31. Security Interest. This Mortgage shall, as to any equipment and
other Personal Property covered hereby, be deemed to constitute a security
agreement, and Mortgagors, as debtors, hereby grant to Mortgagee, as secured
party, a security interest therein pursuant to the Massachusetts Uniform
Commercial Code. Mortgagors agree, upon request of Mortgagee, to furnish an
inventory of Personal Property owned by Mortgagors and subject to this Mortgage
and, upon request by Mortgagee, to execute any supplements to this Mortgage, any
separate security agreement and any financing statements and continuation
statements in order to include specifically said inventory of Personal Property
or otherwise to perfect the security interest granted hereby, subject always to
the limitation of liability provided for in Section 16 of the Note. Upon any
Event of Default, Mortgagee shall have all of the rights and remedies provided
in said Code or otherwise

                                      -82-

<PAGE>



provided by law or by this Mortgage, including but not limited to the right to
require Mortgagors to assemble such Personal Property and make it available to
Mortgagee at a place to be designated by Mortgagee which is reasonably
convenient to both parties, the right to take possession of the Personal
Property with or without demand and with or without process of law and the right
to sell and dispose of the same and distribute the proceeds according to law.
The parties hereto agree that any requirement of reasonable notice shall be met
if Mortgagee sends such notice to Mortgagors at least ten (10) days prior to the
date of sale, disposition or other event giving rise to the required notice, and
that the proceeds of any disposition of any such Personal Property may be
applied by Mortgagee first to the reasonable expenses in connection therewith,
including reasonable attorneys' fees and legal expenses incurred, and then to
payment of the Indebtedness. With respect to the Personal Property that has
become so attached to the Real Property that an interest therein arises under
the real property law of the Commonwealth of Massachusetts, this Mortgage shall
also constitute a financing statement and a fixture filing under the
Massachusetts Uniform Commercial Code. Mortgagors are the record owners of the
Real Property and the addresses of Mortgagors and Mortgagee are as set forth on
the first page of this Mortgage.

     32. Right of Entry. Mortgagee and Mortgagee's representatives may at all
reasonable times and without notice to Mortgagors if there exists an Event of
Default (otherwise, upon reasonable advance notice) enter upon the Security and
inspect the same, or cause it to be inspected by agents, employees or


                                      -83-
<PAGE>


independent contractors of Mortgagee, and show the same to others, but Mortgagee
shall not be obligated to make any such entry or inspection.

     33. Estoppel Certificate. Mortgagors, within fifteen (15) days after
written request from Mortgagee, will furnish a signed statement in writing, duly
acknowledged, of the amount then due or outstanding hereunder and, to the best
of their knowledge, whether or not any offsets or defenses exist against the
Indebtedness, and if so, specifying such offsets and defenses. Mortgagee, within
fifteen (15) days after written request from Mortgagors, will furnish a signed
statement in writing, duly acknowledged, of the amount then due and outstanding
hereunder and, to the best of its knowledge, whether or not any default exists
under this Mortgage or any of the other Loan Documents, and if so, specifying
such default. Mortgagors shall, within fifteen (15) days following Mortgagee's
request, execute and deliver a current landlord estoppel certificate with
respect to the leases at the Security. If required by law or regulatory
authority, Mortgagors shall, upon Mortgagee's request, exercise any right it may
have to request an estoppel certificate from any or all of the tenants at the
Security; and, in such event, Mortgagee shall pay Mortgagors' reasonable costs
of preparing, requesting and negotiating such tenant estoppel certificates.

     34. Annual Statements. Mortgagors shall, within one hundred twenty (120)
days after the end of each fiscal year of Mortgagors, deliver to Mortgagee (a)
annual statements audited and certified (subject only to such qualifications as
are reasonably acceptable



                                      -84-
<PAGE>

to Mortgagee) by Coopers & Lybrand or another independent Certified Public
Accountant reasonably satisfactory to Mortgagee, together with any "Notes to
Financial Statements" prepared by such accountant in connection with such audit
and certification, all prepared in accordance with generally accepted accounting
principles and showing in detail: (i) a balance sheet for the Security as of the
last day of such fiscal year; (ii) a statement of earnings from the Security for
such fiscal year showing, among other things, all rents and other income
therefrom and all expenses paid or incurred in connection with the operation of
the Security, and (iii) a statement of operating cash flows for the Security;
and (b) a statement signed by Mortgagors listing all leases of space in the
Improvements as of the last day of such fiscal year, the respective areas
demised thereunder, the names of the tenants, the respective expiration dates of
the leases, the respective rentals provided for therein, accounts receivable and
such other information as may reasonably be requested by Mortgagee. In addition,
Mortgagors agree to provide Mortgagee with unaudited quarterly cash flow reports
and a current rent roll. Mortgagors also agree to provide Mortgagee with a pro
forma income statement and current expense statement for the current and prior
calendar year by January 31 of the current year.

          If Mortgagors omit to prepare and deliver promptly any report required
by this Section, following notice and the expiration of the cure period provided
for in Section 26(b) hereof, Mortgagee may elect, in addition to exercising any
remedy for an Event of Default as provided for in this Mortgage, to make an
audit of all books and records of Mortgagors, including bank


                                      -85-
<PAGE>

accounts, which in any way pertain to the Security, and to prepare the statement
or statements which Mortgagors failed to procure and deliver. Such audit shall
be made and such statements shall be prepared by an independent Certified Public
Accountant to be selected by Mortgagee. Mortgagors shall pay all expenses of
such audit and related services, which expenses shall be secured hereby as part
of the Indebtedness and shall be immediately due and payable upon demand with
interest thereon at the Default Rate from the date of demand.

          Mortgagee shall afford any information received pursuant to this
Section the same degree of confidentiality that Mortgagee affords similar
information proprietary to Mortgagee; provided, however, that Mortgagee does not
in any way warrant or represent that such information received from Mortgagors
will remain confidential; and, provided further, that Mortgagee shall have the
unconditional right to disclose, as necessary, any such information in the event
Mortgagee sells, transfers, conveys, or assigns the Mortgage or any portion of
the Indebtedness.

     35. Rights Cumulative. Each right and remedy of Mortgagee under this
Mortgage, the Note and the other Loan Documents shall be in addition to every
other right and remedy of Mortgagee and such rights and remedies may be enforced
separately or in any combination.

     36. Subrogation. To the extent that proceeds of the Indebtedness are used
to pay any outstanding lien, charge or encumbrance affecting the Security, such
proceeds shall be deemed

                                      -86-
<PAGE>


to have been advanced by Mortgagee at Mortgagors' request, and Mortgagee shall
be subrogated to all rights, interest and liens owned or held by any owner or
holder of such outstanding liens, charges and encumbrances, irrespective of
whether such liens, charges or encumbrances are released of record; provided,
however, that the terms and provisions hereof (including, without limitation,
Section 40 of this Mortgage) shall govern the rights and remedies of Mortgagee
and shall supersede the terms, provisions, rights, and remedies under the lien
or liens to which Mortgagee is subrogated hereunder.

     37. No Waiver. Any failure by Mortgagee to insist upon the strict
performance by Mortgagors of any of the terms and provisions hereof shall not be
deemed to be a waiver of any of the terms and provisions hereof, and Mortgagee,
notwithstanding any such failure, shall have the right thereafter to insist upon
the strict performance by Mortgagors of any and all of the terms and provisions
hereof to be performed by Mortgagors.

     38. Mortgage Extension. The lien hereof shall remain in full force and
effect during any postponement or extension of the time of payment of the
Indebtedness, or of any part thereof, and any number of extensions or
modifications hereof, of the Note or of any additional notes taken by Mortgagee,
shall not affect the lien hereof or the liability of Mortgagors or of any
subsequent obligor to pay the Indebtedness unless and until such lien or
liability be expressly released in writing by Mortgagee.



                                      -87-
<PAGE>

     39. Indemnification. Mortgagors shall indemnify and hold Mortgagee harmless
from and against all obligations, liabilities, losses, costs, expenses, fines,
penalties or damages (including attorneys' fees) which Mortgagee may incur by
reason of injury to persons or damage to property arising out of (i) tenant
improvement work or other construction work in or upon the Security by
Mortgagors or others claiming by, through or under Mortgagors, (ii) the
operation or maintenance of the Security by Mortgagors, or (iii) any other
action or inaction by, or matter which is the responsibility of, Mortgagors.
Mortgagors shall defend Mortgagee against any claim or litigation involving
Mortgagee for the same, and should Mortgagee incur such obligation, liability,
loss, cost, expense, fine, penalty or damage, then Mortgagors shall reimburse
Mortgagee upon demand. Any amount owed Mortgagee under this Section 39 shall
bear interest at the Default Rate from the date of demand therefor and shall be
secured hereby.

     40. Scope of Liability. The provisions of Section 16 of the Note are hereby
incorporated by reference herein. As previously noted in Section 15 hereof, the
Indemnitors have executed a separate Environmental Indemnification Agreement to
reflect their liability for environmental matters regarding the Security,
subject to the limitations of liability set forth therein.

     41. Attorneys' Fees. Any reference to "attorney fees", "attorneys' fees",
or "attorney's fees" in this document includes but is not limited to both the
fees, charges and costs incurred by Mortgagee through its retention of outside
legal counsel and the

                                      -88-
<PAGE>



allocable fees, costs and charges for services rendered by Mortgagee's in-house
counsel. Any reference to "attorney fees", "attorneys' fees", or "attorney's
fees" shall also include but not be limited to those attorneys or legal fees,
costs and charges incurred by Mortgagee in the collection of any Indebtedness,
the enforcement of any obligations hereunder, the protection of the Security,
the foreclosure of this Mortgage, the sale of the Security in lieu of
foreclosure, the defense of actions arising hereunder and the collection,
protection or setoff of any claim the Mortgagee may have in a proceeding under
Title 11, United States Code. Attorneys' fees provided for hereunder shall
accrue whether or not Mortgagee has provided notice of default or of an
intention to exercise its remedies for an Event of Default. All such attorneys'
fees, charges and costs shall be reasonable.

     42. Administrative Fees. Mortgagee shall have the right to charge
reasonable administrative fees during the term of the Note as Mortgagee may
determine, in its reasonable discretion, in connection with any servicing
requests made by Mortgagors requiring Mortgagee's evaluation, preparation and
processing of any such requests. Administrative fees shall not be charged for
routine servicing matters contemplated by the Loan Documents including, without
limitation: processing payments; processing insurance and UCC continuation
documentation; processing escrow draws; review of tenant leases, subordination,
non-disturbance and attornment agreements and tenant estoppels on standard forms
approved by Mortgagee without material modifications. Such administrative fees
shall apply without limitation to requests for matters not permitted or
contemplated by the Loan Documents



                                      -89-
<PAGE>

(including, without limitation: requests for transfers or assignments; and
requests for review of new easements), and to requests, which, while
contemplated by the Loan Documents, because of the nature of the request, will
require significantly more time than an institutional lender, acting reasonably,
would contemplate for such request (including without limitation, requests for
the approval of tenant leases, tenant estoppels and tenant subordination,
non-disturbance and attornment agreements which contain material differences
from Mortgagors' or Mortgagee's standard forms (including any standard changes
approved by Mortgagee, which for this purpose will be considered part of the
standard form)). Mortgagee shall also be entitled to reimbursement for
professional fees it incurs for such administration, including without
limitation, those of architects, engineers and attorneys' fees (whether (i)
employed by Mortgagee or its affiliate or (ii) engaged by Mortgagee or its
affiliates as independent contractors).

     43. Protection of Security; Costs and Expenses. Mortgagors shall appear in
and defend any action or proceeding purporting to affect the security hereof or
the rights or powers of Mortgagee, and shall pay all reasonable costs and
expenses, including without limitation cost of evidence of title and reasonable
attorneys' fees, in any such action or proceeding in which Mortgagee may appear,
and in any suit brought by Mortgagee to foreclose this Mortgage upon the
occurrence of an Event of Default or to enforce or establish any other rights or
remedies of Mortgagee hereunder upon the occurrence of an Event of Default. If
Mortgagors fail to perform any of the covenants or agreements contained in this


                                      -90-
<PAGE>


Mortgage, or if any action or proceeding is commenced which affects Mortgagee's
interest in the Security or any part thereof, including, but not limited to,
eminent domain, code enforcement, or proceedings of any nature whatsoever under
any federal or state law, whether now existing or hereafter enacted or amended,
relating to bankruptcy, insolvency, arrangement, reorganization or other form of
debtor relief, then if an Event of Default exists hereunder (or, if no Event of
Default exists hereunder, if Mortgagors fail, within thirty (30) days after
notice by Mortgagee to Mortgagors [or such shorter notice period as the
exigencies of the situation may require], to take appropriate action to correct
such failure, etc., subject, however, to Mortgagors' contest rights under this
Mortgage, to the extent applicable) Mortgagee may, but without obligation to do
so and without further notice to or demand upon Mortgagors and without releasing
Mortgagors from any obligation hereunder, make such appearances, disburse such
sums and take such action as Mortgagee reasonably deems necessary or appropriate
to protect Mortgagee's interest, including, but not limited to, disbursement of
reasonable attorneys' fees, entry upon the Security to make repairs or take
other action to protect the security hereof, and payment, purchase, contest or
compromise of any encumbrance, charge or lien, other than the Permitted
Encumbrances, which in the judgment of Mortgagee appears to be prior or superior
hereto. Mortgagors further agree to pay all reasonable expenses of Mortgagee
(including without limitation attorneys' fees and disbursements) incident to the
protection of the rights of Mortgagee hereunder, or to enforcement or collection
of payment of the Indebtedness, whether by judicial or non-judicial proceedings,
or in connection with any bankruptcy,


                                      -91-
<PAGE>


insolvency, arrangement, reorganization or other debtor relief proceeding of
Mortgagors, or otherwise in connection with an Event of Default. Any amounts
disbursed by Mortgagee pursuant to this Section shall be additional indebtedness
of Mortgagors secured by the Loan Documents as of the date of disbursement and
shall bear interest at the Default Rate from the date of demand therefor. All
such amounts shall be payable by Mortgagors immediately upon demand. Nothing
contained in this Section shall be construed to require Mortgagee to incur any
expense, make any appearance, or take any other action.

     44. Notices. Any notice, demand, request, statement or consent made
hereunder shall be in writing, signed by the party giving such notice, request,
demand, statement, or consent, and shall be delivered personally or delivered to
a reputable overnight delivery service providing a receipt addressed as set
forth below or to such other address within the continental United States of
America as theretofore may have been designated in writing by such party in
accordance with the terms of this Section 44. The effective date of any notice
given as provided in this Section shall be the date of personal service or one
(1) business day after delivery to such overnight delivery service, whichever is
applicable. As used herein, the phrase "business day" or "business days" shall
mean any calendar day(s) other than a Saturday, a Sunday or a Federal or a State
holiday on which the U.S. Postal Service offices are closed for business. For
purposes hereof, the addresses are as follows:


                                      -92-
<PAGE>


If to Mortgagee:           Connecticut General Life Insurance Company
                           c/o CIGNA Investments, Inc.
                           900 Cottage Grove Road
                           Hartford, Connecticut  06152-2313
                           Attn:  Investment  Services,  S-313

With a copy to:            CIGNA Corporation
                           Investment Law Department
                           900 Cottage Grove Road
                           Hartford, Connecticut 06152-2215
                           Attn: Real Estate Division, S-215A

If to one or more
Mortgagors:                Beacon Properties, L.P.
                           Wellesley Holding, L.P.
                           Wellesley Holding II, L.P
                           c/o Beacon Properties Corporation
                           50 Rowes Wharf
                           Boston, Massachusetts 02110
                           Attn: Mr. Robert J. Perriello,
                                 Chief Financial Officer

with a courtesy
copy to:                   Goulston & Storrs
                           400 Atlantic Avenue
                           Boston, Massachusetts 02110-3333
                           Attn: Harold Stahler, Esq.


          Notwithstanding the foregoing agreement to provide courtesy copies,
such copies shall be courtesy copies only, and failure to provide such courtesy
copies shall have absolutely no effect or entitle Mortgagors to any remedy
whatsoever. Any notice duly given to Mortgagors shall be effective whether or
not the courtesy copies were given.

     45. Release/Partial Release. Upon the satisfaction in full of the
Indebtedness, Mortgagee shall release of record the Security from the lien
hereof and from the lien of any other Loan Document securing the indebtedness
and shall surrender this Mortgage, the other Loan Documents and all notes
evidencing indebtedness secured by this Mortgage to Mortgagors. Mortgagors shall
pay all costs of recordation.


                                      -93-
<PAGE>


     Prior to the satisfaction in full of the Indebtedness, Mortgagee agrees to
release up to two properties from the lien of this Mortgage, provided that all
of the following conditions have been satisfied:

          (i)  A pay-down of the outstanding Principal Indebtedness under the
               Note is made by Mortgagors to Mortgagee with respect to each
               building comprising the Security according to the following
               schedule:

               Release Property:                         Loan Pay-Down Required:
               -----------------                         -----------------------
                                                    
               65 William Street                         $2,904,000
               60 William Street                          5,408,000
               55 William Street                          5,510,000
               40 William Street                          7,370,000
               20 William Street                         13,180,000
               45 William Street                         15,740,000
               80 William Street                          7,130,000
               100 William Street                         4,300,000
                                             
          (ii) The loan-to-value ratio of the outstanding Principal Indebtedness
               under the Note to the fair market value of the Security
               (determined by obtaining an appraisal of the Security which will
               remain immediately following such release in form and substance
               reasonably acceptable to Mortgagee prepared by an MAI


                                      -94-
<PAGE>


               certified appraiser reasonably acceptable to Mortgagee), in
               Mortgagee's reasonable opinion, will not exceed 65%;

          (iii) There shall exist no Event of Default under the Loan Documents
               and no monetary default and no non-monetary default of which
               notice has been given to Mortgagors;

          (iv) All information and documents requested by Mortgagee relating to
               such release shall be submitted to Mortgagee at least sixty (60)
               days prior to closing and must be reasonably satisfactory to
               Mortgagee in form and substance;

          (v)  Mortgagors shall provide Mortgagee with evidence, including, if
               necessary, written consent to such release by any lienholder
               subordinate to the Mortgage, if any, that such release will not
               affect the priority of the Mortgage on the remainder of the Real
               Property;

          (vi) Mortgagors shall pay all of Mortgagee's reasonable expenses,
               including all of Mortgagee's local and staff attorneys' fees, in
               connection with the release;



                                      -95-
<PAGE>


          (vii) Mortgagors shall pay Mortgagee a $25,000 administrative fee for
               each request for a partial release covering one property or
               covering two properties so long as both properties are to be
               released substantially contemporaneously;

          (viii) Mortgagee shall receive such title endorsements as it may
               reasonably require, including, without limitation, partial
               release endorsements;

          (ix) If the remaining Real Property depends on the released Real
               Property with respect to any of the following, there shall be in
               effect such easement and other similar agreements running with
               the land and benefitting the remaining Real Property and
               providing for vehicle access, parking, utilities, maintenance,
               repair and insurance in form and substance as Mortgagee deems
               reasonably necessary; and

          (x)  Mortgagors shall provide evidence to Mortgagee, in form and
               substance reasonably acceptable to Mortgagee, that following such
               partial release the remaining Security will comply with all
               applicable legal requirements which Mortgagee reasonably
               determines may be affected by such partial release, including,


                                      -96-
<PAGE>

               without limitation, subdivision, zoning and other land use
               restrictions.

     From and after Mortgagee's receipt of the partial Loan prepayment, the debt
service payments payable under the Note from and after the Interest Only Period
(defined in the Note) shall be proportionately reduced, based upon the portion
of the Principal Indebtedness (defined in the Note) which is prepaid pursuant to
this Section 45.

     46. Applicable Law. The provisions hereof shall be construed in accordance
with the laws of the Commonwealth of Massachusetts.

     47. Invalidity. If any provision of this Mortgage shall be held invalid or
unenforceable, the same shall not affect in any respect whatsoever the validity
of the remainder of this Mortgage, except that if such provision provides for
the payment of the Principal Indebtedness (as defined in the Note) and/or
interest payable under the Note or any escrow deposits payable under any of the
other Loan Documents, and such provision is rendered invalid or unenforceable in
a material respect, then Mortgagee may, at its option, declare the Indebtedness
due and payable upon one hundred eighty (180) days prior written notice to
Mortgagors and, provided there exists no Event of Default hereunder, without
prepayment fee.


                                      -97-
<PAGE>

     48. Captions. The captions in this instrument are inserted only as a matter
of convenience and for reference, and are not and shall not be deemed to be any
part hereof.

     49. Modifications. This Mortgage may not be changed or terminated except in
writing signed by both parties. The provisions of this Mortgage shall extend and
be applicable to all renewals, amendments, extensions, consolidations, and
modifications of the other Loan Documents, and any and all references herein to
the Loan Documents shall be deemed to include any such renewals, amendments,
extensions, consolidations or modifications thereof.

     50. Bind and Inure. The provisions of this Mortgage shall be binding on the
Mortgagors and their respective heirs, successors and assigns, and any
subsequent owners of the Security. The covenants of Mortgagors herein shall run
with the land, and this Mortgage and all of the covenants herein contained shall
inure to the benefit of the Mortgagee, its successors and assigns.

     51. Replacement of Note. Upon receipt of evidence reasonably satisfactory
to Mortgagors of the loss, theft, destruction or mutilation of the Note, and in
the case of any such loss, theft or destruction, upon delivery of an indemnity
agreement reasonably satisfactory to Mortgagors or, in the case of any such
mutilation, upon surrender and cancellation of the Note, Mortgagors will execute
and deliver, in lieu thereof, a replacement note, identical in form and
substance to the Note and


                                      -98-
<PAGE>


dated as of the date of the Note and upon such execution and delivery all
references in this Mortgage to the Note shall be deemed to refer to such
replacement note.

     52. Time of the Essence. Time is of the essence with respect to the intent,
meaning, construction and enforcement of each and every covenant, agreement and
obligation of Mortgagors under this Mortgage, the Note and the other Loan
Documents subject to any force majeure exceptions provided for thereunder.

     53. Statutory Condition; Statutory Power of Sale. This Mortgage is upon the
STATUTORY CONDITION for any breach of which, or upon the breach of any other of
Mortgagors' covenants and undertakings hereunder, in each case, following the
expiration of applicable notice and cure periods provided for in Section 26
hereof, Mortgagee shall have the STATUTORY POWER OF SALE.

     54. ERISA Provisions. Mortgagee is entering into the Loan Documents in part
on behalf of both its Separate Account 5W, The Sedgwick James, Inc. Savings and
Profit Sharing Plan (sometimes hereinafter referred to as "SA 5W") and Separate
Account BET, the 401(k) Retirement Savings Plan for Certain Represented
Employees of Bethlehem Steel Corporation and Subsidiary Companies (sometimes
hereinafter referred to as "SA BET"). SA 5W and SA BET are "separate accounts"
as defined in Section 3(17) of the Employee Retirement Income Security Act of
1974, as amended ("ERISA"). Mortgagee is therefore subject to the fiduciary
obligation provisions of ERISA and as a result may be prohibited by law from
engaging in certain transactions. Each Mortgagor

                                      -99-
<PAGE>



hereby represents and warrants to Mortgagee that neither Mortgagor, the General
Partners of any Mortgagor, nor any person directly or indirectly, through one or
more intermediaries, controlling, controlled by, or under common control with
them (an "affiliate") have, and during the immediately preceding one year have
not exercised, the authority to appoint or terminate Mortgagee as an asset
manager of The Sedgwick James, Inc. Savings and Profit Sharing Plan (the
"Sedgwick James Plan") or the 401(k) Retirement Savings Plan for Certain
Represented Employees of Bethlehem Steel Corporation and Subsidiary Companies
(the "Bethlehem Steel Plan") or the authority to negotiate the terms of
Mortgagee's management agreement with or on behalf of the Sedgwick James Plan or
the Bethlehem Steel Plan (such authority being referred to herein as the
"disqualifying powers"). For purposes of determining who is an affiliate, the
term "control" means the power to exercise a controlling influence over the
management or the policies of a person other than an individual.


     Notwithstanding any other provision in this Mortgage, each Mortgagor
represents, warrants and covenants that, during the term of the Loan, the
General Partners of each Mortgagor will not transfer a direct partnership
interest in such Mortgagor, and no Mortgagor will sell the Real Property, to an
entity unless such entity represents to Mortgagee that neither it nor its
affiliates have the disqualifying powers. Mortgagee has been informed by The
Sedgwick James, Inc. and Bethlehem Steel Corporation that, currently, no party
other than The Sedgwick James, Inc. and Bethlehem Steel Corporation and their
respective Plan Investment

                                     -100-
<PAGE>


Committees have the disqualifying powers and Mortgagee agrees to cooperate with
each Mortgagor, upon such Mortgagor's request, in determining which entities
have disqualifying powers. Upon request, Mortgagee agrees to notify each
Mortgagor whether Mortgagee has been informed that other entities have the
disqualifying powers and the identity of such entities.

     Mortgagors agree to indemnify and hold Mortgagee harmless from, against and
with respect to, and to be responsible for, any costs, expense or damage
(including reasonable attorney's fees) resulting from a breach of the
Mortgagors' representations, warranties and covenants contained in this Section
54.

     IN WITNESS WHEREOF, Mortgagors have duly executed this Mortgage as a sealed
instrument on the day and year first above written.


                               Mortgagors:

                               WELLESLEY HOLDING, L.P.

                               By:    Beacon Properties, L.P.

                                      By:    Beacon Properties Corporation

                                             By:  /s/ Robert J. Perriello
                                                  -----------------------------
                                                  Name: Robert J. Perriello
                                                  Title: Senior Vice President

                                             By:  /s/ Nancy J. Broderick
                                                  -----------------------------
                                                  Name:   Nancy J. Broderick
                                                  Title: Treasurer



                                     -101-
<PAGE>



                                WELLESLEY HOLDING II, L.P.

                                By:    Beacon Properties Corporation

                                       By: /s/ Robert J. Perriello
                                           -----------------------------
                                           Name: Robert J. Perriello
                                           Title: Senior Vice President

                                       By: /s/ Nancy J. Broderick
                                           -----------------------------
                                           Name:   Nancy J. Broderick
                                           Title:  Treasurer


                                BEACON PROPERTIES, L.P.

                                By:    Beacon Properties Corporation

                                       By: /s/ Robert J. Perriello
                                           -----------------------------
                                           Name: Robert J. Perriello
                                           Title: Senior Vice President

                                       By: /s/ Nancy J. Broderick
                                           -----------------------------
                                            Name:   Nancy J. Broderick
                                            Title:  Treasurer



                          COMMONWEALTH OF MASSACHUSETTS

Suffolk, SS.                                                    January 8, 1996


     Then personally appeared Robert J. Perriello and Nancy J. Broderick, the
Senior Vice President and Treasurer, respectively, of Beacon Properties
Corporation, General Partner of Wellesley Holding II, L.P. and of Beacon
Properties, L.P., General Partner of Wellesley Holding, L.P., and acknowledged
the foregoing to be their free act and deed and the free act and deed of Beacon
Properties Corporation, Beacon Properties, L.P., Wellesley Holding, L.P. and
Wellesley Holding II, L.P., before me.

                                 /s/ Cheray G. Shein
                                ----------------------------
                                Notary Public
                                My Commission Expires: February 24, 2000



                    


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