Alerted that British regulars planned to seize colonial military supplies and possibly arrest rebel leaders Samuel Adams and John Hancock, Boston's Sons of Liberty dispatched riders into the Massachusetts countryside. Revere's ride, later mythologized by Longfellow, helped rouse militia companies who would clash with British troops the next morning at Lexington, opening the American Revolutionary War.
Around 10 p.m., silversmith Paul Revere was rowed across the Charles River and set off on a borrowed horse named Brown Beauty, racing through Charlestown, Medford, and Menotomy to warn that British troops were heading toward Concord. William Dawes took a separate route out through Boston Neck. Both men knew the countryside intimately and used prearranged signals, including two lanterns hung in Boston's Old North Church steeple, to confirm the British were crossing the Charles by boat rather than marching over land.
Revere never actually shouted 'The British are coming' — most colonists still considered themselves British and the phrase would have been meaningless. Instead he warned that 'the Regulars are coming out.' He reached Lexington around midnight, warned Hancock and Adams, then continued toward Concord with Dawes and a third rider, Samuel Prescott, before being captured and briefly detained by a British patrol.
The warning worked. Militia companies mustered before dawn, and by morning shots rang out on Lexington Green, the first blood of a war that would create a nation.