Also a native of Virginia, Clark was born Aug. 1, 1770, on a plantation in Caroline County. At the age of 14, Clark and his family moved to a plantation in Kentucky on the frontier. He entered the army as a militiaman in 1789 and fought in campaigns against the Indians in the Ohio Valley. In 1792, he became an officer in the regular army and continued to fight in frontier campaigns until 1796, when he resigned to manage his family's plantation. After accepting Lewis' invitation, Clark became a co-leader of the "Corps of Discovery" in 1803. After the expedition, Clark was promoted to Brigadier General and Thomas Jefferson appointed him to the Superintendency of Indian Affairs in 1807. In 1813, Clark went on to serve as governor of the newly formed Missouri Territory, where he worked to strengthen the territory's defenses against hostile Indians and establish friendly relations with local tribes along the Missouri and Mississippi Rivers. He lived the rest of his life in St. Louis and died Sept. 1, 1838.