[1] He attended Boston Latin School the College of New Jersey (now Princeton University), graduating in 1774.

[3] Starting in 1795, Mason was a partner in the Mount Vernon Proprietors, a developer of real estate in Boston's Beacon Hill neighborhood.

[4] Mason was also a member of the South Boston Association, which developed real estate in Dorchester.

[2] He served again in the U.S. House of Representatives from March 4, 1817, to May 15, 1820, whereupon he resigned to pursue his law practice.

Elizabeth was involved in running the Home for Aged Colored Women in Boston, as well as the Children's Aid Society and the Woman's Education Association.