(1743–1826), 3rd president of the US 1801–09. A Democratic-Republican from Virginia, he played a key role in leadership during the American Revolution and was the principal drafter of the Declaration of Independence 1776. While president, he secured the Louisiana Purchase 1803 and authorized the Lewis-Clark expedition to explore this territory. Re-elected to a second term, his poor handling of US shipping and maritime policy made a third term impossible. He chartered the University of Virginia 1819 and served as its head.