In May 1776, British troops began to arrive at Quebec City, where they broke the Continental Army's siege. The British chased the American forces back to Ticonderoga in June and, after several months of shipbuilding, moved down Lake Champlain under Guy Carleton in October. The British destroyed a small fleet of American gunboats in the Battle of Valcour Island in mid-October, but snow was already falling, so the British retreated to winter quarters in Quebec. About 1,700 troops from the Continental Army, under the command of Colonel Anthony Wayne, wintered at Ticonderoga. The British offensive resumed the next year in the Saratoga campaign under General John Burgoyne. During the summer of 1776, the Americans, under the direction of General Schuyler, and later under General Horatio Gates, added substantial defensive works to the area. Mount Independence, which is almost completely surrounded by water, was fortified with trenches near the water, a horseshoe battery part way up the side, a citadel at the summit, and redoubts armed with cannons surrounding the summit area. These defenses were linked to Ticonderoga with a pontoon bridge that was protected by land batteries on both sides. The works on Mount Hope, the heights above the site of Montcalm's victory, were improved to include a star-shaped fort. Mount Defiance remained unfortified. In March 1777, American generals were strategizing about possible British military movements and considered an attempt on the Hudson River corridor a likely possibility. General Schuyler, heading the forces stationed at Ticonderoga, requested 10,000 troops to guard Ticonderoga and 2,000 to guard the Mohawk River valley against British invasion from the north. George Washington, who had never been to Ticonderoga (his only visit was to be in 1783), believed that an overland attack from the north was unlikely, because of the alleged impregnability of Ticonderoga. This, combined with continuing incursions up the Hudson River valley by British forces occupying New York City, led Washington to believe that any attack on the Albany area would be from the south, which, as it was part of the supply line to Ticonderoga, would necessitate a withdrawal from the fort. As a result, no significant actions were taken to further fortify Ticonderoga or significantly increase its garrison. The garrison, about 2,000 men under General Arthur St. Clair, was too small to man all the defenses.