In late June 1776, as a massive British fleet prepared to invade New York, a complex drama played itself out at the headquarters of General George Washington’s Continental Army in New York City: a former bodyguard of the general was set to be hanged for conspiracy against the Patriot rebellion—and against Washington, himself.

On June 28, some 20,000 people gathered in a field just north of the city and watched a private in the Continental Army mount the gallows on charges of sedition, mutiny and treachery. The doomed man was Thomas Hickey, an Irish-born former British soldier who had joined the rebel cause after the outbreak of war in 1775- History