Exhibit 1

AGREEMENT

JOINT FILING OF SCHEDULE 13D

The undersigned hereby agree to jointly prepare and file with regulatory authorities this Schedule 13D and any future amendments thereto reporting each of the undersigned’s ownership of securities of CommonWealth REIT, and hereby affirm that such Schedule 13D is being filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the other, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

Date: March 8, 2013	CORVEX MANAGEMENT LP
	By:	/s/ Keith Meister
		Keith Meister
		Managing Partner
Date: March 8, 2013	KEITH MEISTER
	By:	/s/ Keith Meister
Date: March 8, 2013	RELATED FUND MANAGEMENT, LLC
	By:	/s/ Richard O’Toole
		Richard O’Toole
		Vice President
Date: March 8, 2013	RELATED REAL ESTATE RECOVERY FUND GP-A, LLC
	By:	/s/ Richard O’Toole
		Richard O’Toole
		Vice President

Date: March 8, 2013	RELATED REAL ESTATE RECOVERY FUND GP, L.P.
	By: Related Real Estate Recovery Fund GP-A, LLC, its general partner
	By: /s/ Richard O’Toole
		Richard O’Toole
		Vice President
Date: March 8, 2013	RELATED REAL ESTATE RECOVERY FUND, L.P.
	By: Related Real Estate Recovery Fund GP, L.P., its general partner
	By: Related Real Estate Recovery Fund GP-A, LLC, its general partner
	By:	/s/ Richard O’Toole
		Richard O’Toole
		Vice President
Date: March 8, 2013	RRERF ACQUISITION, LLC
	By:	/s/ Richard O’ Toole
		Richard O’Toole