The American Revolution was a political upheaval during the last half of the 18th century in which thirteen colonies in North America joined together to break from the British Empire, combining to become the United States of America. They first rejected the authority of the Parliament of Great Britain to govern them from overseas without representation, and then expelled all royal officials. By 1775 each colony had established a Provincial Congress or an equivalent governmental institution to govern itself, but still recognized the British Crown and their inclusion in the empire. The British responded by sending combat troops to re-establish royalist control. Through the Second Continental Congress, the Americans then managed the armed conflict in response to the British known as the American Revolutionary War.
The British sent invasion armies and used their powerful navy to blockade the coast. George Washington became the American commander, working with Congress and the states to raise armies and neutralize the influence of Loyalists. Claiming the rule of George III of Great Britain was tyrannical and therefore illegitimate, Congress declared independence as a new nation in July 1776, when Thomas Jefferson wrote and the states unanimously ratified the United States Declaration of Independence. The British lost Boston in 1776, but then captured and held New York City. The British would capture the revolutionary capital at Philadelphia in 1777, but Congress escaped, and the British withdrew a few months later.