Thomas Jefferson was the main author of the Declaration of Independence, a seminal document adopted on July 4, 1776. Jefferson was a leading figure in the American Enlightenment and strongly advocated for individual rights and the principles of liberty. His work on the Declaration eloquently articulated the colonies' grievances against British rule and emphasized the right to "life, liberty, and the pursuit of happiness." Jefferson's writing not only declared the colonies' independence but also laid the foundation for democratic ideals worldwide. The document is considered one of the cornerstones of American democracy and is celebrated for its profound influence on political thought.