Two historic Commonwealth Avenue properties sold for an undisclosed amount this week.

The rare Louis Comfort Tiffany-designed Ayer Mansion in Boston, as well as a property located at 397-399 Commonwealth Ave., sold off market on Monday. Listed at $22.500 million, the 395 Commonwealth Ave. Ayer Mansion property has 25,300 square feet of living space.

The sellers were represented by Regina Winslow and Mark O’Donnell of William Raveis Real Estate. The final closing number is yet to be determined, due to potential additional square footage of the other property.

Built in 1899-1900, the Ayer Mansion was designed for Frederick Ayer and his wife by architect Alfred J. Manning and designer Louis Comfort Tiffany. It has five floors of art-filled living space and features a four-story hanging chandelier and a grand center staircase, along with 12,650 square feet of living area, a full, finished basement, an elevator that services all floors and three double-tandem parking spaces. 

The property is a designated national historic landmark and has a Preservation Restriction Agreement to preserve its architectural, archaeological and historic integrity. 

The historic property at 397-399 Commonwealth Ave. was built in 1924-1925. The five-story building has 12,650 square feet of living space. The current owner purchased the property in 1974 turning it into the Bayridge Residence and Cultural Center.