Thomas Jefferson primarily authored the Declaration of Independence, a foundational document in American history adopted on July 4, 1776. This document articulated the American colonies' desire for independence from British rule, emphasizing Enlightenment ideals such as individual rights and self-governance. Jefferson’s eloquent prose encapsulated the colonies' grievances against King George III and asserted the principles of liberty and equality. The Declaration served not only as a formal assertion of independence but also as an inspiration for democratic movements worldwide, influencing future human rights declarations and constitutions.