[Explanation For the purposes of this section, the pendency of a suit or proceeding shall be deemed to commence from the date of the presentation of the plaint or the institu 184 tion of the proceeding in a Court of competent jurisdiction, and to continue until the suit or proceeding has been disposed of by a final decree or order, and complete satisfaction or discharge of such decree or order has been obtained, or has be come unobtainable by reason of the expiration of any period of limitation prescribed for the execution thereof by any law for the time being in force.]" Material provisions of section 58 (a) and (b) of the said Act are in the following terms: "(a) A Mortgage is the transfer of an interest in specific immovable property for the purpose of securing the payment of money advanced or to be advanced by way of loan, an existing or future debt, or the performance of an engagement which may give rise to a pecuniary liability.