The military career of Benedict Arnold in 1775 and 1776 covers many of the military actions that occurred in the northernmost Thirteen Colonies early in the American Revolutionary War. Arnold began the war as a captain in Connecticut's militia, a position to which he was elected in March 1775. Following the outbreak of hostilities at Lexington and Concord the following month, his company marched northeast to assist in the siege of Boston that followed. Arnold proposed to the Massachusetts Committee of Safety an action to seize Fort Ticonderoga in New York, which he knew was poorly defended. They issued a colonel's commission to him on May 3, 1775, and he immediately rode off to the west, where he arrived at Castleton in the disputed New Hampshire Grants (present-day Vermont) in time to participate with Ethan Allen and his men in the capture of Fort Ticonderoga. He followed up that action with a bold raid on Fort Saint-Jean on the Richelieu River north of Lake Champlain. He then resigned his Massachusetts commission after a command dispute with the head of a detachment of Connecticut militia troops that arrived in June to reinforce Ticonderoga.