On the night of April 18, 1775, General Gage sent 700 men to seize munitions stored by the colonial militia at Concord, Massachusetts. Riders including Paul Revere alerted the countryside, and when British troops entered Lexington on the morning of April 19, they found 77 minutemen formed up on the village green. Shots were exchanged, killing several minutemen. The British moved on to Concord, where a detachment of three companies was engaged and routed at the North Bridge by a force of 500 minutemen. As the British retreated back to Boston, thousands of militiamen attacked them along the roads, inflicting great damage before timely British reinforcements prevented a total disaster. With the Battles of Lexington and Concord, the war had begun.