Perhaps African American genealogy researchers who have connected with African American ancestors, who were free in Virginia before or during the early 1800s, particularly in Loudoun, Prince William, Fairfax, Westmoreland and some other Tidewater Counties in Virginia, should take a close look at the list of enslaved African Americans emancipated by Robert Carter III (1728-1804), in a gradual emancipation plan that began in 1791 and extended at least until 1820. Carter's emancipation of around 500 enslaved African Americans is thought to be the largest such action by a private slave owner in U.S. Hisory.
http://www.henryrobertburke.com/id10.html
Henry Robert Burke