News of the battles of Lexington and Concord spread within days. In Virginia, Thomas Jefferson observed that “a phrenzy of revenge seems to have seized all ranks of people,” causing the royal governor of Virginia, Lord Dunmore, to remove all gunpowder from the Williamsburg powder house to a ship, out of reach of angry Virginians. He also threatened to arm slaves, if necessary, to ward off attacks by colonists. This threat proved effective for several months.

In November 1775, as the crisis deepened, Dunmore issued an official proclamation promising freedom to defecting able-bodied slaves who would fight for the British. Dunmore had no intention of liberating all slaves, and astute blacks noticed that Dunmore neglected to free his own slaves. A Virginia barber named Caesar declared that “he did not know any one foolish enough to believe him [Dunmore], for if he intended to do so, he ought first to set his own free.” Within a month some fifteen hundred slaves had joined Dunmore’s “Ethiopian Regiment.” Camp diseases quickly set in: dysentery, typhoid fever, and smallpox. When Dunmore sailed for England in mid-1776, he took three hundred black survivors with him. But the association of freedom with the British authorities had been established, and throughout the war thousands more southern slaves fled their masters whenever the British army was close enough to offer safe refuge.

In the northern colonies as well, slaves clearly recognized the evolving political struggle with Britain as an ideal moment to bid for freedom. A twenty-one-year-old Boston domestic slave employed biting sarcasm in a 1774 newspaper essay to call attention to the hypocrisy of local slave owners: “How well the Cry for Liberty, and the reverse Disposition for exercise of oppressive Power over others agree,—I humbly think it does not require the Penetration of a Philosopher to Determine.” This extraordinary young woman, Phillis Wheatley, had already gained international recognition through a book of poems published in London in 1773. Wheatley’s poems spoke of “Fair Freedom” as the “Goddess long desir’d” by Africans enslaved in America. Wheatley’s master freed the young poet in 1775.

From north to south, groups of slaves pressed their case. Several Boston blacks offered to fight for the British in exchange for freedom, but General Gage turned them down. In Maryland, a planter complained that blacks impatient for freedom had to be disarmed of about eighty guns along with some swords. In North Carolina, white suspicions about a planned slave uprising led to the arrest of scores of African Americans who were ordered to be whipped by the revolutionary committee of public safety.

By 1783, when the Revolutionary War ended, as many as twenty thousand blacks had voted against slavery with their feet by seeking refuge with the British army. About half failed to achieve the liberation they were seeking, instead succumbing to disease, especially smallpox, in refugee camps. But some eight thousand to ten thousand persisted through the war, and later, under the protection of the British army, left America to start new lives of freedom in Canada’s Nova Scotia or Africa’s Sierra Leone.