Martha Green was born in Prince George County, Virginia on May 8, 1734. In 1750 she married William Williamson in Amelia County, Virginia, and the couple eventually settled in Bute County, North Carolina. In 1768 Daniel, an enslaved man owned by the Williamsons, killed William Williamson by poisoning him. Martha Williamson received money when the local court executed Daniel for the crime. By 1771 Martha had remarried and changed her last name to Cox. She died in Warren County, North Carolina in about 1821.