On April 14, 1775, Sir Thomas Gage, who was Commander-in-Chief, North America, from 1763 to 1775 and appointed Governor of Massachusetts in 1774, received orders from Britain to take action against the Patriots. Acting on intelligence, Gage planned to destroy stores of militia ordnance at Concord by way of Lexington and to capture John Hancock and Samuel Adams, considered the two principal instigators of the rebellion. The operation was to commence before midnight on April 19 and surprise the militia while completing their objectives and retreating to Boston before multitudes of patriot militias could respond. However, Patriot intelligence, which Paul Revere had helped organize, learned of Gage's intentions, and Revere alerted Captain John Parker, commander of the Concord militia. The first action of the war was a brief skirmish at Lexington, followed by a full-scale battle during the Battles of Lexington and Concord. After suffering some 300 casualties, British troops withdrew to Boston, followed by local militia who laid siege to the city.