A section of this colonial mansion may date from the earliest settlement of Cambridge, as seen in an eight-foot-square chimneystack in the west end of the house. John Vassall bought the house a century later, and sold it to his brother Henry, who lived here from 1741 to 1769, substantially enlarging and remodeling the property; Henry's nephew John built a new house nearby at 105 Brattle. Five bays wide on Brattle Street, under a double-hipped roof and dormers, the clap-boarded house has been divided into two residences with entrances on the sides. During the Revolution, the United States Army used the Vassall House as its medical headquarters. In 1872, Samuel Batchelder subdivided the surviving property. Along the Brattle Street sidewalk stands a wall of early concrete block (1870).