Isabella Stewart Gardner Museum just bought an apartment building. Here’s why.

The museum agreed to pay $22.8 million to acquire the complex.

In an unusual move, the Isabella Stewart Gardner Museum has shelled out $22.8 million to enter the real estate business.

The Boston museum acquired the 62-unit multifamily building at 14 Palace Road and 11 Tetlow St., located behind its new wing, to prevent redevelopment that could threaten its mission.

“The interest in this space was for two reasons: to ensure that there was no major renovation or demolition that could put at risk our collection and historic property; and, to ensure that the visitor’s experience in and around the Museum would not be adversely impacted by a new, undetermined use of the property in the future,” Donna Hardwick, a spokesperson for the museum, said in a statement.

Hardwick said the museum was first alerted to the opportunity to purchase the historic residential property last winter.

The museum has a strong relationship with the former owners, which allowed it to contact the family about purchase options.

The purchase of the Tetlow and Palace Road properties is unrelated to the fundraising or grants the museum has in place to support the exhibitions, programming and restoration projects, according to museum officials.

The museum has already brought in a property management firm to handle all aspects of the property, including day-to-day operations, tenant relations, and maintenance.

The property will remain a residential property, which is at 98% occupancy.

“We believe this was the best decision for the neighborhood as it will have zero impact on the community, our neighbors and visitors to our historic Museum,” Hardwick said in a statement.

On Tuesday, CBRE, a commercial real estate services and investment firm, announced the sale of the Joy Realty Portfolio, a 284-unit, eight-building apartment portfolio in two separate transactions in Boston’s Fenway and Longwood neighborhoods. The sale included the property behind the museum.

CBRE represented the seller, a private family who owned some of the assets for over 100 years. The sale marks the first time the portfolio has sold.

Cambridge-based Forest Properties acquired the remainder of the portfolio, 137 and 143 Park Drive and 24,28, 32-34 and 46 Westland Ave., which comprise 222 units.

Built in the early 1900s, CBRE says the portfolio comprises a mix of studios through four bedrooms, with an average size of 550 square feet. The buildings are a mix of four- and five-story buildings.

Beth Treffeisen is a general assignment reporter for Boston.com, focusing on local news, crime, and business in the New England region.