The event that marked the beginning of the American Revolution in 1776 was the issuance of the Declaration of Independence. On July 4, 1776, the Continental Congress officially adopted this document, which proclaimed the Thirteen Colonies' intention to separate from British rule. The Declaration, primarily authored by Thomas Jefferson, articulated the colonies' grievances against King George III and outlined the Enlightenment ideals of individual rights and government by consent. This bold declaration not only galvanized support for independence but also established a new vision for governance based on liberty and democracy, igniting a conflict that would lead to the establishment of the United States.