Throughout 1775, tensions had been rising between Virginian patriots and their royalist governor, Lord Dunmore. The War of Independence had broken out earlier that year, in Lexington, Mass., but not a single shot had been fired in the South. Virginia’s patriots managed to uphold a boycott against British goods, but it was far from clear that most Virginians would join the patriots’ side. Many remained neutral, wary of casting their lot with a ragtag militia that dared to fight one of the mightiest militaries in the world.

Then, on Oct. 26, 1775, the war crossed the Mason-Dixon line. The two sides exchanged fire at Hampton, Va., after patriots burned a beached British ship, the Liberty, to a charred-out shell. The Battle of Hampton lasted less than a day, with both sides retreating. But it set in motion a sequence of events that led many neutral southerners to support a war they had at first embraced only tepidly. Critical to those events was Dunmore’s formal proclamation, in early November, granting freedom to slaves who fought for his army. Though not as well-known as early battles in the North, like Bunker Hill, the Battle of Hampton was a pivotal moment in the nascent conflict, bringing the war to the South by preying upon southerners’ worst fear: a full-blown slave revolt.

Thomas Jefferson directly alluded to that fear in the initial draft of the Declaration of Independence in the summer of 1776. In his list of grievances against the British, Jefferson, a Virginian slave-owner, included the crime of “exciting those very people”—slaves—“to rise in arms among us.” The outrage that Jefferson and many like him expressed at the arming of slaves has led historians like Woody Holton to argue that what slaves did at Hampton “indirectly helped motivate White Virginians to declare independence from Britain.”

Despite Dunmore’s Proclamation, and Jefferson’s rhetoric, a full-scale slave revolt never materialized. Yet at least 1,000 slaves escaped their masters and joined Dunmore’s all-Black Ethiopian Regiment, including George Washington’s own slave, Harry. By the end of the war, from 20,000 to 100,000 enslaved Blacks—as many as one in five enslaved Africans from all 13 states—ran to British lines.

Read it at Slate.