A venture involving Washington investment giant Carlyle Group has acquired part of a former diocesan property near the Downingtown Country Club, where it plans a 220-unit apartment building.

The private-equity and asset-management firm is joining Malvern developer Eli Kahn and Cornerstone Tracy LLC of Villanova on the project at Lancaster Avenue and Woodbine Road, Kahn said Wednesday.

The group acquired the property in August for $5.25 million from Kahn’s E. Kahn Development Corp., according to the real estate tracker CoStar Group. Chester County property records put the development site at 16.7 acres.

Kahn bought a 50-acre parcel that includes that land from the Archdiocese of Philadelphia for $3.8 million in 2014, the Philadelphia Business Journal reported at the time. The archdiocese continues to operate its St. John Vianney Center treatment clinic on property adjacent to the project site.

Carlyle’s other area holdings include stakes in the Commonwealth apartment building in Center City and the 3737 Chestnut apartments in University City. It previously held an interest in the now-defunct Philadelphia Energy Holdings refinery complex in South Philadelphia.

Kahn’s other projects include Devon Yards, an upscale shopping center at the former Waterloo Gardens nursery site.