Thomas Jefferson (April 13, 1743 - July 4, 1826) was an American Founding Father who served as the third president of the United States from 1801 to 1809. He was the primary author of the Declaration of Independence. Following the American Revolutionary War and prior to becoming president in 1801, Jefferson was the nation's first U.S. secretary of state under George Washington and then the nation's second vice president under John Adams. Jefferson was a leading proponent of democracy, republicanism, and natural rights, and he produced formative documents and decisions at the state, national, and international levels.