The Congress faced the task of conducting a war already in progress. Fighting had begun with the Battle of Lexington and Concord on April 19, and Congress needed to create an official army out of the untrained assemblage of militia laying siege on Boston.
The transformation of these rebels into the Continental Army was assisted by the victory of the Vermont and Massachusetts militia under the joint command of Ethan Allen and Benedict Arnold at the British garrison at Ticonderoga on Lake Champlain. Their major achievement was to confiscate enough British cannon to make the Patriot militias into an army capable of an artillery barrage.
Allen and more than 100 of his Green Mountain Boys had already decided to take the fort when Arnold arrived with formal military commissions from Massachusetts and Connecticut and a militia of his own. The Green Mountain Boys were unwilling to follow anyone but Allen into battle, so Allen and Arnold shared command as the Patriot militia surprised and overwhelmed the 50 Redcoats in the isolated garrison, who were completely unaware of the bloodshed in Massachusetts. The cannon seized at Ticonderoga and the next day at Crown Point, also on Lake Champlain, allowed the new Continental Army under General George Washington to drive the British from Boston the following spring.
Ironically, both Allen and Arnold would eventually be accused of treason against the Patriot cause they had served so well in its earliest and neediest moments. Allen avoided conviction for his attempt to reattach Vermont to the British empire in the unstable days of the new republic. Arnold’s name, however, became synonymous with traitor for his attempt to sell the fort at West Point, New York, to the British in 1780.—History.com