On May 10, 1775, American forces led by Ethan Allen and Benedict Arnold capture Fort Ticonderoga in New York. The fort contains a much needed supply of military equipment including cannons which are then hauled to Boston by ox teams.
Also on May 10, 1775, The Second Continental Congress convenes in Philadelphia, with John Hancock elected as its president. On May 15, the Congress places the colonies in a state of defense. On June 15, the Congress unanimously votes to appoint George Washington general and commander-in-chief of the new Continental Army.
These references are from The History Place about the American Revolution.