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                                                                     Exhibit 4.5

                                 TRUST AGREEMENT
                                       OF
                             MARKEL CAPITAL TRUST II

     THIS TRUST AGREEMENT is made as of October 15, 2001 (this "Trust
Agreement"), by and among Markel Corporation, a Virginia corporation, as sponsor
(the "Sponsor"), and Chase Manhattan USA, a National Association (the
"Trustee"). The Sponsor and the Trustee hereby agree as follows:

     1. The trust created hereby shall be known as "Markel Capital Trust II"
(the "Trust") in which name the Trustee or the Sponsor, to the extent provided
herein, may conduct the business of the Trust, make and execute contracts, and
sue and be sued.

     2. The Sponsor hereby assigns, transfers, conveys and sets over to the
Trust the sum of ten dollars ($10.00). Such amount shall constitute the initial
trust estate. It is the intention of the parties hereto that the Trust created
hereby constitute a business trust under Chapter 38 of Title 12 of the Delaware
Code, 12 Del. C. (S) 3801, et seq. (the "Business Trust Act"), and that this
document constitute the governing instrument of the Trust. The Trustee is hereby
authorized and directed to execute and file a certificate of trust with the
Delaware Secretary of State in accordance with the provisions of the Business
Trust Act.

     3. The Sponsor and the Trustee will enter into an amended and restated
Trust Agreement or Declaration satisfactory to each such party to provide for
the contemplated operation of the Trust created hereby and the issuance of the
Preferred Securities and the Common Securities referred to therein. Prior to the
execution and delivery of such amended and restated Trust Agreement or
Declaration, the Trustee shall not have any duty or obligation hereunder or with
respect of the trust estate, except as otherwise required by applicable law or
as may be necessary to obtain prior to such execution and delivery any licenses,
consents or approvals required by applicable law or otherwise. Notwithstanding
the foregoing, the Trustee may take all actions deemed proper as are necessary
to effect the transactions contemplated herein.

     4. The Sponsor, as the sponsor of the Trust, is hereby authorized, in its
discretion, (i) to prepare and file with the Securities and Exchange Commission
(the "Commission") and to execute, in each case on behalf of the Trust, (a) a
Registration Statement (the "1933 Act Registration Statement"), including all
pre-effective and post-effective amendments thereto, relating to the
registration under the Securities Act of 1933, as amended (the "1933 Act"), of
the Preferred Securities of the Trust and (b) a Registration Statement on Form
8-A (the "1934 Act Registration Statement"), including all pre-effective and
post-effective amendments thereto, relating to the registration of the Preferred
Securities of the Trust under the Securities Exchange Act of 1934, as amended;
(ii) if and at such time as determined by the Sponsor, to file with the New York
Stock Exchange or any other exchange or the National Association of Securities
Dealers (each, an

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"Exchange"), and execute on behalf of the Trust one or more listing applications
and all other applications, statements, certificates, agreements and other
instruments as shall be necessary or desirable to cause the Preferred Securities
of the Trust to be listed on any of the Exchanges; (iii) to negotiate, execute,
deliver and perform on behalf of the Trust an underwriting agreement with one or
more underwriters relating to the offering of the Preferred Securities of the
Trust; and (iv) to file and execute on behalf of the Trust, such applications,
reports, surety bonds, irrevocable consents, appointments of attorney for
service of process and other papers and documents that shall be necessary or
desirable to register the Preferred Securities of the Trust under the securities
or "Blue Sky" laws of such jurisdictions as the Sponsor, on behalf of the Trust,
may deem necessary or desirable.

     In the event that any filing referred to in this Section 4 is required by
the rules and regulations of the Commission, any Exchange or state securities or
"Blue Sky" laws to be executed on behalf of the Trust by the Trustees, the
Trustees, in their capacities as trustees of the Trust, are hereby authorized to
join in any such filing and to execute on behalf of the Trust any and all of the
foregoing, it being understood that the Trustees, in their capacities as
trustees of the Trust, shall not be required to join in any such filing or
execute on behalf of the Trust any such document unless required by the rules
and regulations of the Commission, an Exchange or state securities or "Blue Sky"
laws.

     5. (a) The Trustees (the "Fiduciary Indemnified Persons") shall not be
liable, responsible or accountable in damages or otherwise to the Trust, the
Sponsor, the Trustees or any holder of the Trust securities (the Trust, the
Sponsor and any holder of the Trust securities being a "Covered Person") for any
loss, damage or claim incurred by reason of any act or omission performed or
omitted by the Fiduciary Indemnified Persons in good faith on behalf of the
Trust and in a manner the Fiduciary Indemnified Persons reasonably believed to
be within the scope of authority conferred on the Fiduciary Indemnified Persons
by this Agreement or by law, except that the Fiduciary Indemnified Persons shall
be liable for any such loss, damage or claim incurred by reason of the Fiduciary
Indemnified Person's gross negligence or willful misconduct with respect to such
acts or omissions.

        (b) The Fiduciary Indemnified Persons shall be fully protected in
relying in good faith upon the records of the Trust and upon such information,
opinions, reports or statements presented to the Trust by any person as to
matters the Fiduciary Indemnified Persons reasonably believes are within such
other person's professional or expert competence and who has been selected with
reasonable care by or on behalf of the Trust, including information, opinions,
reports or statements as to the value and amount of the assets, liabilities,
profits, losses, or any other facts pertinent to the existence and amount of
assets from which distributions to holders of Trust securities might properly be
paid.

     6. The Sponsor agrees to the fullest extent permitted by applicable law,

        (a) to indemnify and hold harmless each Fiduciary Indemnified Persons,
or any of its officers, directors, shareholders, employees, representatives or
agents, from and against any loss,

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damage, liability, tax, penalty, expense or claim of any kind or nature
whatsoever incurred by the Fiduciary Indemnified Persons by reason of the
creation, operation or termination of the Trust in a manner the Fiduciary
Indemnified Persons reasonably believed to be within the scope of authority
conferred on the Fiduciary Indemnified Persons by this Trust Agreement, except
that no Fiduciary Indemnified Persons shall be entitled to be indemnified in
respect of any loss, damage or claim incurred by the Fiduciary Indemnified
Persons by reason of gross negligence or willful misconduct with respect to such
acts or omissions; and

         (b) to advance expenses (including legal fees) incurred by a Fiduciary
Indemnified Person in defending any claim, demand, action, suit or proceeding
shall, from time to time, prior to the final disposition of such claim, demand,
action, suit or proceeding, upon receipt by the Trust of an undertaking by or on
behalf of such Fiduciary Indemnified Persons to repay such amount if it shall be
determined that such Fiduciary Indemnified Person is not entitled to be
indemnified as authorized in the preceding subsection.

     7.  The provisions of Section 6 shall survive the termination of this Trust
Agreement or the earlier resignation or removal of the Fiduciary Indemnified
Persons.

     8.  The Trust may terminate without issuing any Trust securities at the
election of the Sponsor.

     9.  This Trust Agreement may be executed in one or more counterparts.

     10. The number of trustees of the Trust initially shall be one and
thereafter the number of trustees of the Trust shall be such number as shall be
fixed from time to time by a written instrument signed by the Sponsor which may
increase or decrease the number of trustees of the Trust; provided, however,
that to the extent required by the Business Trust Act, one trustee of the Trust
shall either be a natural person who is a resident of the State of Delaware or,
if not a natural person, an entity which has its principal place of business in
the State of Delaware. Subject to the foregoing, the Sponsor is entitled to
appoint or remove without cause any trustee of the Trust at any time. Any
trustee of the Trust may resign upon thirty days' prior notice to the Sponsor.

     11. This Trust Agreement shall be governed by, and construed in accordance
with, the laws of the State of Delaware (without regard to conflict of laws
principles).

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     IN WITNESS WHEREOF, the parties hereto have caused this Trust Agreement to
be duly executed as of the day and year first above written.

                        MARKEL CORPORATION,
                          as Sponsor

                        By:   /s/ Gregory B. Nevers
                              ---------------------------------------
                              Name: Gregory B. Nevers
                              Title: Sr. Vice President & General Counsel


                        CHASE MANHATTAN BANK USA,
                        NATIONAL ASSOCIATION
                        not in its individual capacity but
                        solely as trustee of the Trust


                        By:   /s/ Michael B. McCarthy
                              ---------------------------------------
                              Name: Michael B. McCarthy
                              Title: Vice President

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