Army, then put British forces in Boston under siege by land, and they withdrew by sea. Each colony formed a Provincial Congress, which assumed power from the former colonial governments, suppressed Loyalism, and contributed to the Continental Army led by Commander in Chief General George Washington. The Patriots unsuccessfully attempted to invade Quebec and rally sympathetic colonists there during the winter of 1775–1776. The Continental Congress declared British King George III a tyrant who trampled the colonists' rights as Englishmen, and they pronounced the colonies free and independent states on July 4, 1776. The Patriot leadership professed the political philosophies of liberalism and republicanism to reject rule by monarchy and aristocracy. The Declaration of Independence proclaimed that all men are created equal, though it was not until later centuries that constitutional amendments and federal laws would incrementally grant equal rights to African Americans, Native Americans, poor white men, and women. The British captured New York City and its strategic harbor in the summer of 1776. The Continental Army captured a British army at the Battle of Saratoga in October 1777, and France then entered the war as an ally of the United States, expanding the war into a global conflict. The British Royal Navy blockaded ports and held New York City for the duration of the war, and other cities for brief periods, but they failed to destroy Washington's forces. Britain's priorities shifted southward, attempting to hold the Southern states with the anticipated aid of Loyalists that never materialized. British general Charles Cornwallis captured an American army at Charleston, South Carolina in early 1780, but he failed to enlist enough volunteers from Loyalist civilians to take effective control of the territory. Finally, a combined American and French force captured Cornwallis' army at Yorktown in the fall of 1781, effectively ending the war. The Treaty of Paris was signed on September 3, 1783, formally ending the conflict and confirming the new nation's complete separation from the British Empire. The United States took possession of nearly all the territory east of the Mississippi River and south of the Great Lakes, with the British retaining control of northern Canada, and French ally Spain taking back Florida. Among the significant results of the American victory were American independence and the end of British mercantilism in America, opening up worldwide trade for the United States—including resumption with Britain. Around 60,000 Loyalists migrated to other British