Little is known about the slaves and slave life at Belvoir. The manor was constructed at a time when wealthy Virginia farmers used slave labor as a diversified agricultural regime. Slaves also worked as skilled tradesmen in the countryside and in cities becoming skilled in trades such as carpentry, masonry, and blacksmithing.
Many slaves were servants in the households of wealthier Virginians such as Belvoir's neighbors George Mason at Gunston Hall and George Washington at Mount Vernon. The servants worked as cooks, butlers, and personal valets and maids.
In one of the few references relating to slaves at Belvoir during the 18th century, William Fairfax, builder of Belvoir, gave slaves to each of his children in his Last Will and Testament.
(Virginia Historical Magazine of History and Biography 4(1) 102). Dated 1756, the instrument included his son, George William Fairfax, who also inherited Belvoir.
... I also give and bequeath unto my said son George Will'm and to his Heirs for ever my Negros named Scipio and Sylvia together with their Issue and Increase, also Pompey...."