 The American Revolutionary War , which began in April 1775 with the Battles of Lexington and Concord , widened in September 1775 when the Continental Army embarked on an invasion of the British Province of Quebec . The province was viewed by the Second Continental Congress as a potential avenue for British forces to attack and divide the rebellious colonies , and was at the time lightly defended . The invasion reached a peak on December 31 , 1775 , when the Battle of Quebec ended in disaster for the Americans . In the spring of 1776 , 10 @,@ 000 British and German troops arrived in Quebec , and General Guy Carleton , the provincial governor , drove the Continental Army out of Quebec and back to Fort Ticonderoga . 
