The signing of the Declaration of Independence on July 4, 1776, marks the event when the thirteen American colonies declared their independence from British rule. Drafted by Thomas Jefferson, the document outlines the philosophical justification for independence, emphasizing the principles of natural rights and government accountability. It proclaimed that all men are created equal and endowed with certain inalienable rights, such as life, liberty, and the pursuit of happiness. The Declaration effectively rallied support for the American Revolution, providing a foundation for the United States' democratic ideals and inspiring movements for independence and human rights worldwide.