Ethan Allen and the Green Mountain Boys captured Fort Ticonderoga on May 10, 1775 by surprising the small British garrison at dawn. They were able to force the fort's surrender and seize over 100 cannons and a large supply of artillery, which were later used to fortify Dorchester Heights and help turn the tide of the Revolutionary War in favor of the colonists. Fort Ticonderoga had changed hands between the French and British over the years and was an important strategic position controlling access via Lake Champlain.