The American Revolution began as a conflict between the thirteen American colonies and Great Britain. The Continental Congress was formed by the colonies to coordinate efforts against Britain and invite others to join the cause for independence. They drafted the Declaration of Independence in 1776 to proclaim that the colonies were free and independent states. After several years of fighting, France joined the Americans as an ally which helped tip the war in their favor. The war culminated with the American victory at Yorktown in 1781. The following year, the Treaty of Paris was signed, granting the colonies their independence and establishing the United States of America.