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                                                                   EXHIBIT 10.39

                       FIRST AMENDMENT TO OPTION AGREEMENT


                  THIS FIRST AMENDMENT TO OPTION AGREEMENT ("FIRST AMENDMENT")
is made as of the ___ day of November, 1996, by and between C/N Horsham Towne
Limited Partnership, a Pennsylvania limited partnership, having an address c/o
The Nichols Company, 16 Campus Boulevard, Newtown Square, Pennsylvania 19073
(hereinafter called "OPTIONOR"), and Brandywine Operating Partnership, L.P., a
Delaware limited partnership, having an address c/o Brandywine Realty Trust, 16
Campus Boulevard, Suite 150, Newtown Square, Pennsylvania 19073 (hereinafter
called "OPTIONEE").

                                   BACKGROUND

                  A. Optionor and Optionee are parties to a certain Option
Agreement dated the 22nd day of August, 1996 (the "AGREEMENT") pursuant to which
Optionor granted to Optionee the right and option (the "OPTION") to acquire
certain tracts or parcels of ground, and all improvements thereon, located at
255, 355, 455 and 555 Business Center Drive, Horsham, Pennsylvania, 19044, all
as more fully described in Exhibit "A" to the Agreement, and therein and herein
referred to as the "Property".

                  B. Optionor and Optionee desire to amend the Agreement to
redefine the Exchange Price (as such term is defined in the Agreement) and for
certain other purposes, all as more fully set forth herein.

                                    AGREEMENT

                  The parties hereto, in consideration of the sum of Ten
($10.00) Dollars, and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, and the mutual covenants and
agreements contained herein, and intending to be legally bound hereby, agree as
follows:

                  1. Paragraph 1 of the Agreement is hereby amended and restated
in its entirety as follows:

                  Optionor does hereby grant to Optionee the right and option
                  (the "OPTION") to acquire the Property for the Exchange Price
                  (as defined below), and otherwise upon the terms and
                  conditions set forth herein. The Optionee may exercise the
                  Option by delivering written notice to the Optionor and New
                  England Mutual Life Insurance Company (the "LENDER") in
                  accordance with Section 16 of this Agreement at any time
                  during the Option Period (as defined below), or during any
                  extension thereof.



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                  2. Paragraph 4 of the Agreement is hereby amended and restated
in its entirety as follows:

                  The Exchange Price for the Property (the "EXCHANGE PRICE")
                  shall be equal to Ten ($10.00) Dollars, plus Optionee's
                  assumption of all sums due and owing under the note, mortgage
                  and any other loan document evidencing or securing the
                  mortgage loan encumbering the Property at the time the Option
                  is exercised.


                  3. Paragraph 6 of the Agreement is hereby amended by the
addition of the following sentence:

                  Consent of the holder of the mortgage on the Property for
                  conveyance of the Property under and subject to the mortgage
                  shall include a statement by the holder as to the status of
                  outstanding defaults thereunder (declared or otherwise), and a
                  confirmation of all sums due and owing under the mortgage
                  obligation as of the date of such statement.


                  4. Paragraph 16 of the Agreement is hereby amended by changing
the notice address for Optionee to the following address:

                           Gerard H. Sweeney, President & CEO
                           Brandywine Realty Trust
                           16 Campus Boulevard
                           Suite 150
                           Newtown Square, PA  19073

                  5. Paragraph 17 of the Agreement is hereby amended and
restated in its entirety as follows:

                  During the term of this Agreement, Optionor shall have the
                  right to fund the costs incurred by Optionor with respect to
                  new leases for space in the Property (including, but not
                  limited to, costs of tenant improvements, brokerage
                  commissions and legal fees) through capital loans made by
                  Optionor or an affiliate for such purpose ("CAPITAL
                  IMPROVEMENT LOANS"). All such Capital Improvement Loans shall
                  bear interest at the prime rate and shall be payable out of
                  cash flow from the Property remaining after payments of third
                  party debt. Upon exercise by Optionee of the Option, Optionor
                  shall advise Optionee if any Improvement Loan

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                  will remain outstanding at Closing hereunder. Optionee shall
                  assume all obligations under any such Capital Improvement
                  Loans outstanding at Closing, and shall indemnify and hold
                  Optionor harmless from any obligations accruing under any such
                  Loan after the date of Closing. Anything herein contained to
                  the contrary notwithstanding, from and after this date,
                  Optionor shall not assume or incur additional indebtedness for
                  capital improvements to the Property without the prior written
                  consent of Optionee, which consent shall not be unreasonably
                  withheld, conditioned or delayed.

                  6. Except to the extent expressly modified hereby, all of the
terms, conditions, covenants and agreements contained in the Agreement shall
remain in full force and effect and unmodified hereby, and as such, the
Agreement is hereby ratified and affirmed by Optionor and Optionee.

                  IN WITNESS WHEREOF, the parties hereto have executed, sealed
and delivered this Agreement the day and year first above written.

                                    OPTIONOR:

                                    C/N HORSHAM TOWNE
                                    LIMITED PARTNERSHIP,
                                    A PENNSYLVANIA LIMITED PARTNERSHIP


                                    BY:______________________________________/S/


                                    OPTIONEE:

                                    BRANDYWINE OPERATING PARTNERSHIP, L.P.
                                             BY:  BRANDYWINE REALTY TRUST,
                                                      ITS GENERAL PARTNER



                                    BY:______________________________________/S/
                                             GERARD H. SWEENEY, PRESIDENT & CEO


                          [Continued on the next page]


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The address of the above-named Optionee is:

c/o      Brandywine Realty Trust
         16 Campus Boulevard
         Suite 150
         Newtown Square, PA  19073


         By:________________________________________
              Name:_________________________________
              Title:________________________________,
                     On behalf of Optionee



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