Thomas Jefferson was an American statesman, diplomat, lawyer, architect, musician, philosopher, and Founding Father who served as the third president of the United States from 1801 to 1809. The principal author of the Declaration of Independence, Jefferson was a proponent of democracy, republicanism, and individual rights, motivating American colonists to break from the Kingdom of Great Britain and form a new nation; he produced formative documents and decisions at both the state and national levels.