Ongoing political tensions between Great Britain and the thirteen colonies reached a crisis in 1774 when the British placed the province of Massachusetts under martial law after the Patriots protested taxes they regarded as a violation of their constitutional rights as Englishmen. When shooting began at Lexington and Concord in April 1775, militia units from across New England rushed to Boston and bottled up the British in the city. The Continental Congress appointed George Washington as commander-in-chief of the newly created Continental Army, which was augmented throughout the war by colonial militia. He drove the British out of Boston but in late summer 1776 they returned to New York and nearly captured Washington's army. Meanwhile, the revolutionaries expelled British officials from the 13 states, and declared themselves an independent nation on July 4, 1776.