The American attack on Quebec in 1775 was a key episode in the build-up to the War of Independence. Capture of the city would give the Americans control of Canada - a strategic disaster for the British. In May 1775 Ethan Allen and Benedict Arnold captured Fort Ticonderoga and Crown Point, but Congress only reluctantly supported proceeding to a full invasion of Canada. Still, Arnold was permitted to lead an expedition to Quebec across modern-day Maine. However, during the 350-mile trek through largely uninhabited wilderness 300 men turned back, while another 150 deserted or died of disease - just 650 reached Quebec. The American siege continued until May, when the thaw brought British reinforcements and relief. More American defeats followed, and soon the British controlled Lake Champlain, but delays in building the fleet had left them insufficient time to recapture Crown Point and Fort Ticonderoga. The Americans were forced to permanently abandon their hopes of bringing Canada into their war of rebellion.