In November, 1813, an American army of some 8000 men, commanded by Major-General James Wilkinson, moved down the St. Lawrence en route to Montreal. Wilkinson was followed and harassed by a British "corp of observation" consisting of about 800 regular militia and Indians commanded by Lieut.-Col. Joseph Morrison. On November 11, Morrison's force, established in a defensive position on John Crysler's farm, was attacked by a contingent of the American army numbering about 4000 men commanded by Brigadier-General J.P. Boyd. The hard fought engagement ended with the Americans' withdrawal from the battlefield. This reverse, in combined with the defeat of another invading army at Chateauguay on October 26, saved Canada from conquest in 1813.