what fort supplied the cannon used to relieve the siege of boston
Siege of Boston In November 1775, Washington sent the 25-year-old bookseller-turned-soldier Henry Knox to bring to Boston the heavy artillery that had been captured at Fort Ticonderoga. In a technically complex and demanding operation, Knox brought many cannons to the Boston area by January 1776. In March 1776, these artillery fortified Dorchester Heights (which overlooked Boston and its harbor), thereby threatening the British supply lifeline. The British commander William Howe saw the British position as indefensible and withdrew the British forces in Boston to the British stronghold at Halifax, Nova Scotia, on March 17 (celebrated today as Evacuation Day).
Battles of Lexington and Concord About 700 British Army regulars in Boston, under Lieutenant Colonel Francis Smith, were given secret orders to capture and destroy Colonial military supplies reportedly stored by the Massachusetts militia at Concord. Through effective intelligence gathering, Patriot leaders had received word weeks before the expedition that their supplies might be at risk and had moved most of them to other locations. On the night before the battle, warning of the British expedition had been rapidly sent from Boston to militias in the area by several riders, including Paul Revere and Samuel Prescott, with information about British plans. The initial mode of the Army's arrival by water was signaled from the Old North Church in Boston to Charlestown using lanterns to communicate "one if by land, two if by sea".