The historical document that declared American independence from Britain is the Declaration of Independence. Drafted primarily by Thomas Jefferson, this pivotal document was adopted by the Continental Congress on July 4, 1776. It articulated the American colonies' grievances against British rule and outlined the philosophical justification for independence, asserting the inherent rights to life, liberty, and the pursuit of happiness. The Declaration's adoption marked the formal beginning of the United States as a separate nation. It has since become a symbol of freedom and democracy, influencing independence movements worldwide.