In September, the French responded by beginning construction of Fort Carillon, later called Fort Ticonderoga, on a point where "La Chute" enters Lake Champlain. These fortifications controlled the easy water route between Canada and colonial New York. A French army, and their native allies under general Louis-Joseph de Montcalm laid siege to Fort William Henry in 1757 and burned it down after the British surrender. During the British retreat to Fort Edward they were ambushed and massacred by natives allied to the French, in what would become known as The Massacre at Fort William Henry.