Exhibit 10.1

[Multiple Properties - FHC]

PURCHASE AND SALE AGREEMENT

by and among

HRPT PROPERTIES TRUST, HUB PROPERTIES TRUST
AND MOB REALTY TRUST,

as Sellers,

and

SENIOR HOUSING PROPERTIES TRUST,

as Purchaser

May 5, 2008

[Multiple Properties - FHC]

TABLE OF CONTENTS

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[Multiple Properties - FHC]

PURCHASE AND SALE AGREEMENT

THIS PURCHASE AND SALE AGREEMENT is made as of May 5, 2008, by and among HRPT PROPERTIES TRUST , a Maryland real estate investment trust (“ HRPT ”), HUB PROPERTIES TRUST , a Maryland real estate investment trust (“ Hub ”), and MOB REALTY TRUST , a Massachusetts nominee trust (“ MOB ”, and together with HRPT and Hub, each a “ Seller ” and collectively, “ Sellers ”), and SENIOR HOUSING PROPERTIES TRUST , a Maryland real estate investment trust (the “ Purchaser ”).

WITNESSETH :

WHEREAS, the Sellers are the owners of the Properties (this and other capitalized terms used and not otherwise defined herein shall have the meanings given such terms in Section 1 ); and

WHEREAS, the Sellers wish to sell to the Purchaser, and the Purchaser desires to purchase from the Sellers, the Properties, subject to and upon the terms and conditions hereinafter set forth;

NOW, THEREFORE , in consideration of the mutual covenants herein contained and other good and valuable consideration, the mutual receipt and legal sufficiency of which are hereby acknowledged, the Sellers and the Purchaser hereby agree as follows:

SECTION 1.                           DEFINITIONS .

Capitalized terms used in this Agreement shall have the meanings set forth below or in the section of this Agreement referred to below:

1.1                                “ Agreement ”  shall mean this Purchase and Sale Agreement, together with any exhibits and schedules attached hereto, as it and they may be amended from time to time as herein provided.

1.2                                “ Allocable Purchase Price ”  shall mean, with respect to each Property, the amount set forth in Schedule A opposite the name of such Property, it being understood and agreed that the aggregate amount of the Allocable Purchase Prices of the Properties shall be One Hundred Twelve Million Nine Hundred Ten Thousand Eight Hundred and Twenty-Four Dollars ($112,910,824).

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1.3                                “ Business Day ”  shall mean any day other than a Saturday, Sunday or any other day on which banking institutions in The Commonwealth of Massachusetts are authorized by law or executive action to close.

1.4                                “ Closing ”  shall have the meaning given such term in Section 2.2 .

1.5                                “ Closing Date ”  shall have the meaning given such term in Section 2.2 .

1.6                                “ Existing Survey ”   shall mean, with respect to each Property, the existing ALTA survey of such Property.

1.7                                “ Existing Title Policy ”   shall mean, with respect to each Property, the existing title insurance policy for such Property.

1.8                                “ Ground Lease ”   shall mean that certain Ground Lease, dated as of November 21, 1994, by and between Hubbard Health Systems, Inc., as landlord, and Fallon Clinic, Inc., as tenant, as modified by that certain Landlord Consent, dated as of September 18, 1996, from Hubbard Health Systems, Inc., as landlord, to Lakeside Realty Company, that certain Assignment of Lease and Consent, dated as of September 30, 1996, by and among Hubbard Health Systems, Inc., as landlord, Fallon Clinic, Inc., as assignor, and Lakeside Realty Company, as assignee, that certain Ground Lease Consent and Estoppel Certificate, dated as of May 9, 1997, from Hubbard Health Systems, Inc., as landlord, to MOB, and that certain Assignment of Ground Lease, dated as of May 14, 1997, by and between Lakeside Realty Company, as assignor, and MOB, as assignee, with respect to the Property located at 340 Thompson Road, Webster, Massachusetts.

1.9                                “ HRPT ”  shall have the meaning given such term in the preambles to this Agreement, together with any permitted successors and assigns.

1.10                          “ Hub ”  shall have the meaning given such term in the preambles to this Agreement, together with any permitted successors and assigns.

1.11                          “ Improvements ”   shall mean, with respect to each Property, the applicable Seller’s entire right, title and interest in and to the existing office buildings, fixtures and other structures and improvements situated on, or affixed to, the Land.

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1.12                          “ Land ”  shall mean, with respect to each Property, the applicable Seller’s entire right, title and interest in and to (a) the parcel(s) of land associated with such Property, which is more particularly described in Schedule B-1 through B-21 hereto, together with (b) all easements, rights of way, privileges, licenses and appurtenances which such Seller may own with respect thereto.

1.13                          “ Leases ”  shall mean the leases identified in the Rent Roll and any other leases hereafter entered into in accordance with the terms of this Agreement.

1.14                          “ MOB ”  shall have the meaning given such term in the preambles to this Agreement, together with any permitted successors and assigns.

1.15                          “ Other Property ”   shall mean, with respect to each Property, the applicable Seller’s entire right, title and interest in and to (a) all fixtures, machinery, systems, equipment and items of personal property owned by such Seller and attached or appurtenant to, located on and used in connection with the ownership, use, operation or maintenance of the Land or Improvements relating to such Property, if any, and (b) all intangible property owned by such Seller arising from or used in connection with the ownership, use, operation or maintenance of the Land or Improvements relating to such Property, if any.

1.16                          “ Permitted Exceptions ”  shall mean, with respect to each Property, collectively, (a) liens for taxes, assessments and governmental charges not yet due and payable or due and payable but not yet delinquent; (b) the Leases relating to such Property; (c) the exceptions to title set forth in the Existing Title Policy for such Property; (d) all matters shown on the Existing Survey for such Property, and (e) such other nonmonetary encumbrances with respect to such Property as may be shown on the Update for such Property which are not objected to by the Purchaser (or which are objected to, and subsequently waived, by the Purchaser) in accordance with Section 3.1 .

1.17                          “ Property ”   shall mean, collectively, all of the Land, the Improvements and the Other Property relating to a single property identified on Schedule A .

1.18                          “ Properties ”  shall mean, collectively, all of the Land, the Improvements and the Other Property relating to the properties identified on Schedule A , the legal descriptions of which are set forth in Schedules B-1 through B-21 .

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1.19                          “ Purchase Price ”  shall mean One Hundred Twelve Million Nine Hundred Ten Thousand Eight Hundred and Twenty-Four Dollars ($112,910,824) (which is the sum of the Allocable Purchase Prices).

1.20                          “ Purchaser ”  shall have the meaning given such term in the preambles to this Agreement, together with any permitted successors and assigns.

1.21                          “ Rent Roll ”  shall mean Schedule C to this Agreement.

1.22                          “ Seller ” and “ Sellers ”  shall have the meanings given such terms in the preambles to this Agreement, together with any permitted successors and assigns.

1.23                          “ Title Company ”  shall mean Lawyers Title Insurance Corporation.

1.24                          “ Update ” and “ Updates ” shall have the meanings given such terms in Section 3.1 .

SECTION 2.                           PURCHASE AND SALE; CLOSING .

2.1                                Purchase and Sale .   In consideration of the payment of the Purchase Price by the Purchaser to the Sellers and for other good and valuable consideration, the Sellers hereby agree to sell to the Purchaser, and the Purchaser hereby agrees to purchase from the Sellers, the Properties for the Purchase Price, subject to and in accordance with the terms and conditions of this Agreement.

2.2                                Closing .   The purchase and sale of the Properties shall be consummated at a closing (the “ Closing ”) to be held at the offices of Sullivan & Worcester LLP, One Post Office Square, Boston, Massachusetts, or at such other location as the Seller and the Purchaser may agree, at 10:00 a.m., local time, on August 8, 2008, as the same may be accelerated pursuant to this Section 2.2 (the “ Closing Date ” ).

Notwithstanding the foregoing, either the Purchaser or the Sellers may accelerate the Closing Date by giving not less than ten (10) Business Days prior written notice (an “ Acceleration Notice ”) to the other, in which event the Closing Date shall be the date set forth in such Acceleration Notice unless the party receiving the Acceleration Notice gives written notice objecting to the accelerated date set forth in the Acceleration Notice (a “ Rejection Notice ”) to the other within five (5) Business Days after its receipt of the Acceleration Notice, in which event,

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the Closing Date shall not be accelerated but shall occur as set forth in the preceding paragraph; provided , however , that the Sellers shall have the right to give a Rejection Notice only if the acceleration of the Closing Date will adversely effect the Sellers’ ability to conclude a like kind exchange pursuant to Section 12.15 , and the Purchaser shall have the right to give a Rejection Notice only if the Purchaser determines, in its reasonable discretion, that the Purchaser does not, or will not, have adequate funds to close on the accelerated Closing Date.

2.3                                Purchase Price .

(a)                                 At Closing, the Purchaser shall pay the Purchase Price to the Sellers, subject to the following adjustments:

(i)                                    There shall be deducted from the Purchase Price the Allocable Purchase Price with respect to any Property as to which this Agreement is terminated pursuant to the terms hereof.

(ii)                                 There shall be added to, or deducted from, the Purchase Price such amounts as may be required by Article 9 .

(b)                                The Purchase Price, as adjusted as provided herein, shall be payable by wire transfer of immediately available funds on the Closing Date to an account or accounts to be designated by the Sellers.

SECTION 3.                                               TITLE, DILIGENCE MATERIALS, ETC .

3.1                                Title .  Prior to the execution of this Agreement, the Sellers have delivered the Existing Title Policy and the Existing Survey for each Property to the Purchaser.

Within ten (10) days after the execution hereof, the Purchaser shall order an update to the Existing Title Policy for each Property (each an “ Update ”, and collectively, the “ Updates ”) from the Title Company.  The Purchaser shall deliver to the Sellers a copy of the Updates promptly upon receipt thereof.  Promptly after receipt of the Updates, but, in any event, prior to the Closing Date, the Purchaser shall give the Sellers written notice of any title exceptions (other than Permitted Exceptions) set forth on any Update as to which the Purchaser objects.  The Sellers shall have the right, but not the obligation, to attempt to remove, satisfy or otherwise cure any exceptions to title to which the Purchaser so objects.  If, for any reason, in their sole discretion, the Sellers are unable

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or unwilling to take such actions as may be required to cause such exceptions to be removed from such Update, the Sellers shall give the Purchaser notice thereof; it being understood and agreed that the failure of the Sellers to give prompt notice of objection shall be deemed an election by the Sellers not to remedy such matters.  If the Sellers shall be unable or unwilling to remove any title defects to which the Purchaser has so objected, the Purchaser may elect (i) to terminate this Agreement only with respect to such Property or (ii) to consummate the transactions contemplated hereby, notwithstanding such title defect, without any abatement or reduction in the Purchase Price on account thereof (whereupon such objected to exceptions or matters shall be deemed to be Permitted Exceptions).  The Purchaser shall make any such election by written notice to the Sellers given on or prior to the fifth (5 ^th ) Business Day after the Sellers’ notice of their unwillingness or inability to cure (or deemed election not to cure) such defect and time shall be of the essence with respect to the giving of such notice.  Failure of the Purchaser to give such notice shall be deemed an election by the Purchaser to proceed in accordance with clause (ii) above.

3.2                                No Other Diligence.   The P urchaser acknowledges that, except as provided in Section 3.1 , (i) the Purchaser has had the opportunity to fully investigate and inspect the physical and environmental condition of the Properties, and to review and analyze all title examinations, surveys, environmental assessment reports, building evaluations, financial data and other investigations and materials pertaining to the Properties which the Purchaser deems necessary to determine the feasibility of the Properties and its decision to acquire the Properties, (ii) the Purchaser shall not be conducting any further title examinations, surveys, environmental assessments, building evaluations, financial analyses or other investigations with respect to the Properties, and (iii) the Purchaser shall not have any right to terminate this Agreement as a result of any title examinations, surveys, environmental assessments, building valuations, financial analyses or other investigations with respect to the Properties.

SECTION 4.                           CONDITIONS TO THE PURCHASER’S OBLIGATION TO CLOSE.

The obligation of the Purchaser to acquire the Properties shall be subject to the satisfaction of the following conditions precedent on and as of the Closing Date:

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4.1                                Closing Documents .  The Sellers shall have delivered, or cause to have been delivered, to the Purchaser the following:

(a)                                 (i) A good and sufficient deed in the applicable form attached as Schedule D hereto, with respect to each Property (other than the Property located at 340 Thompson Road, Webster, Massachusetts), in proper statutory form for recording, duly executed and acknowledged by the applicable Seller, conveying title to such Property, free from all liens and encumbrances other than the Permitted Exceptions, or (ii) with respect to the Property located at 340 Thompson Road, Webster, Massachusetts, an assignment by MOB and an assumption by the Purchaser, in form and substance reasonably satisfactory to MOB and the Purchaser, duly executed and acknowledged by MOB and the Purchaser, of all of MOB’s right, title and interest in, to and under the Ground Lease, as applicable;

(b)                                An assignment by the applicable Seller and an assumption by the Purchaser, with respect to each Property, in form and substance reasonably satisfactory to such Seller and the Purchaser, duly executed and acknowledged by such Seller and the Purchaser, of all of such Seller’s right, title and interest in, to and under the Leases and all of such Seller’s right, title and interest, if any, in, to and under all transferable licenses, contracts, permits and agreements affecting such Property; !

(c)                                 A bill of sale by the applicable Seller, with respect to each Property, without warranty of any kind, in form and substance reasonably satisfactory to such Seller and the Purchaser, with respect to any personal property owned by such Seller, situated at such Property and used exclusively by such Seller in connection with such Property (it being understood and agreed that no portion of the Purchase Price is allocated to personal property);

(d)                                To the extent the same are in any Seller’s possession, original, fully executed copies of all material documents and agreements, plans and specifications and contracts, licenses and permits pertaining to the Properties;

(e)                                 To the extent the same are in any Seller’s possession, duly executed original copies of the Leases;

(f)                                   A closing statement, with respect to each Property, in form and substance reasonably satisfactory to the applicable Seller and the Purchaser, duly executed and acknowledged by such Seller and the Purchaser, showing the Allocable Purchase Price,

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apportionments and fees, and costs and expenses paid in connection with the Closing; and

(g)                                Such other conveyance documents, certificates, deeds and other instruments as the Purchaser, the Sellers or the Title Company may reasonably require and as are customary in like transactions in sales of property in similar transactions.

4.2                                Ground Lease Consent and Estoppel .  The Purchaser shall have obtained a ground lease consent and estoppel certificate, in form and substance reasonably satisfactory to the Purchaser, dated within thirty (30) days prior to the Closing Date, with respect to the Ground Lease.

4.3                                Title Policy .  The Title Company shall be prepared to issue, upon payment of the title premium at its regular rates, a title policy in the amount of the Allocable Purchase Price for each Property, insuring title to such Property is vested in the Purchaser or its designee or assignee, subject only to the Permitted Exceptions, with such endorsements as shall be reasonably required by the Purchaser.

4.4                                Environmental Reliance Letters.   The Purchaser shall have received a reliance letter with respect to each Property, authorizing the Purchaser and its designees and assignees to rely on the most recent environmental assessment report prepared for such Property, in form and substance reasonably acceptable to t he Purchaser.

4.5                                Condition of Property.   Each Property shall be in substantially the same physical condition as on the date of this Agreement, ordinary wear and tear and, subject to Section 10.1 , casualty excepted.

4.6                                Other Conditions .

(a)                                 All representations and warranties of the Sellers herein shall be true, correct and complete in all material respects on and as of the Closing Date and the Sellers shall have performed in all material respects all covenants and obligations required to be performed by the Sellers on or before the Closing Date.

(b)                                In the event that the conditions set forth in this Section 4 have been satisfied with respect to less than all of the Properties, Purchaser shall not be relieved of any obligation hereunder with respect to those Properties which are not subject to such unsatisfied conditions.

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SECTION 5.                           CONDITIONS TO SELLERS’ OBLIGATION TO CLOSE .

The obligation of the Sellers to convey the Properties to the Purchaser is subject to the satisfaction of the following conditions precedent on and as of the Closing Date:

5.1                                Purchase Price .   The Purchaser shall deliver to the Sellers the Purchase Price payable hereunder, subject to the adjustments set forth in Section 2.3 , together with any closing costs to be paid by the Purchaser under Section 9.2 .

5.2                                Closing Documents .  The Purchaser shall have delivered to the Sellers duly executed and acknowledged counterparts of the documents described in Section 4.1 , where applicable.

5.3                                Ground Lease Consent and Estoppel .  The Purchaser shall have obtained a ground lease consent and estoppel certificate, in form and substance reasonably satisfactory to the Purchaser, dated within thirty (30) days prior to the Closing Date, with respect to the Ground Lease.

5.4                                Other Conditions .

(a)                                 All representations and warranties of the Purchaser herein shall be true, correct and complete in all material respects on and as of the Closing Date and the Purchaser shall have performed in all material respects all covenants and obligations required to be performed by the Purchaser on or before the Closing Date.

(b)                                In the event that the conditions set forth in this Section 5 have been satisfied with respect to less than all of the Properties, Sellers shall not be relieved of any obligation hereunder with respect to those Properties which are not subject to such unsatisfied conditions.

SECTION 6.                           REPRESENTATIONS AND WARRANTIES OF SELLERS .

To induce the Purchaser to enter into this Agreement, the Sellers represent and warrant to the Purchaser as follows:

6.1                                Status and Authority of the Seller, Etc.   Each Seller is duly organized, validly existing and in good standing under the laws of its state of organization or formation, and has all requisite power and authority under its charter documents to enter into and perform its obligations under this Agreement and to consummate the transactions contemplated hereby.

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6.2                                Action of the Seller, Etc.   Each Seller has taken all necessary action to authorize the execution, delivery and performance of this Agreement, and upon the execution and delivery of any document to be delivered by any Seller on or prior to the Closing Date, this Agreement and such document shall constitute the valid and binding obligation and agreement of such Seller, enforceable against such Seller in accordance with its terms, except as enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium or similar laws of general application affecting the rights and remedies of creditors.

6.3                                No Violations of Agreements .  Neither the execution, delivery or performance of this Agreement by any Seller, nor compliance with the terms and provisions hereof, will result in any breach of the terms, conditions or provisions of, or conflict with or constitute a default under, or result in the creation of any lien, charge or encumbrance upon any Property pursuant to the terms of any indenture, mortgage, deed of trust, note, evidence of indebtedness or any other agreement or instrument by which such Seller is bound.

6.4                                Litigation .  To the Sellers’ actual knowledge, no Seller has received written notice that any investigation, action or proceeding is pending or threatened, which (i) questions the validity of this Agreement or any action taken or to be taken pursuant hereto, or (ii) involves condemnation or eminent domain proceedings against any Property or any portion thereof.

6.5                                Existing Leases, Etc.   Subject to Section 8.1 , other than the Leases listed in the Rent Roll, no Seller has entered into a contract or agreement with respect to the occupancy of any Property that will be binding on the Purchaser after the Closing.  To the Sellers’ actual knowledge: (a) the copies of the Leases heretofore delivered by the Sellers to the Purchaser are true, correct and complete copies thereof; and (b) the Leases have not been amended except as evidenced by amendments similarly delivered and constitute the entire agreement between the applicable Seller and the tenants thereunder.  Except as otherwise set forth in the Rent Roll or the Leases: (i) to the Sellers’ actual knowledge, each of the Leases is in full force and effect on the terms set forth therein; (ii) to the Sellers’ actual knowledge, there are no uncured defaults or circumstances which with the giving of notice, the passage of time or both would constitute a default thereunder which would have a material adverse effect on the business or operations of any Property; (iii) to the Sellers’ actual knowledge, each of their

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tenants is legally required to pay all sums and perform all material obligations set forth therein without any ongoing concessions, abatements, offsets, defenses or other basis for relief or adjustment; (iv) to the Sellers’ actual knowledge, none of their tenants has asserted in writing or has any defense to, offsets or claims against, rent payable by it or the performance of its other obligations under its Lease which would have a material adverse effect on the on-going business or operations of any Property; (v) no Seller has any outstanding obligation to provide any of its tenants with an allowance to perform, or to perform at its own expense, any tenant improvements; (vi) none of their tenants has prepaid any rent or other charges relating to the post-Closing period; (vii) to the Sellers’ actual knowledge, none of their tenants has filed a petition in bankruptcy or for the approval of a plan of reorganization or management under the Federal Bankruptcy Code or under any other similar state law, or made an admission in wr