Even in the months after Union general Benjamin F. Butler adopted a policy of liberating contraband, Virginia slaves had wisely chosen to watch events, fearing Union lines were too far to reach or dreading the cost of failure. But after confederate general Robert E. Lee called upon the War Department to commandeer “52 negroes to work on fortifications” and labor for the dangerous “Nitre and Mining Bureau,” both slaves and free blacks had no choice but to risk everything by making their way toward Washington.
A number of high-ranking Confederates and influential whites lost slaves in the mass exodus. After John A. Washington, the late president’s great-grandnephew, rode south to join the Confederate army, the slaves at his Mount Vernon estate took advantage of his absence to liberate themselves. Some marched down the Potomac for the capital. Others waited nearby until they deemed it safe, moved back into their old cabins, and began to support themselves as free farmers and hired hand. Closer still to Lincoln’s White House were the sixty-three bondsmen and bondwomen owned by Mary Custis Lee at Arrington plantation. When Mary’s father, George Washington Parke Custis, died in 1857, he stipulated in his will that his slaves were all to be freed within five years, a promise to which he alerted his slaves. But Mary’s husband and her father’s executor, then-colonel Robert E. Lee, believed that unfree labor was crucial to improving Arlington House’s financial status. He rented eleven of them away to nearby whites and sent others to the family’s Pamunkey River estates. When bondman Wesley Norris and his cousin Mary tried to escape in 1859, Lee instructed his overseer to give them fifty and twenty lashes, respectively; on leave from the military, Lee watched to ensure that the stripes were laid “on well.” In accordance with his father-in-law’s instructions, Lee officially freed Mary’s slaves on December 29, 1862, but by that date, her plantation had been seized by federal troops and her slaves had found freedom across the river in Washington.
– The Wars of Reconstruction The Brief, Violent History of America’s Most Progressive Era by Douglas R. Egerton