Rosemont's first development project was the adaptive reuse and historic renovation of the Friary, in Brookline . This project is where Rosemont took its name.

The history of the site began at the end of the 19 th century. William Hartley, a successful wool merchant, originally built Rosemont in 1902. The estate consisted of the main house and a carriage house, sitting on a 2-acre parcel in the Aspinwall Hill section of Brookline , which was one of the early suburbs developed beyond the Back Bay . In 1916 the property was purchased by the archdiocese of Boston to serve as the residence of Cardinal O'Connell. After he died in 1927, his estate sold the property to the Order of St. Francis, which used it as a Friary, or residence for the Friars. At that time, the carriage house was expanded, and converted into a Chapel on the lower level, and a dormitory on the upper level.

In 1995 Rosemont acquired the Friary and working closely with the Town Planning Board, developed plans for residential development that preserved the character of the existing estate. The main house was sold without any renovation. The Chapel was converted into a three-unit condominium, and five new homes were carefully sited on the balance of the property. The design of the new building incorporated features and materials of the two original buildings, such as Weymouth seam face granite, cedar shingles, and exposed rafters and framing. In addition, special care was taken to insure that a grove of 150-year-old oak trees was preserved during and after construction.

Rosemont received an award from the Town of Brookline Historic Preservation Commission in recognition of the superior planning and design that preserved the historical character of the site.

This project was completed in 1996.