Meriwether Lewis and William Clark met each other in 1794, when Clark was Lewis' commanding officer in the Army. After Lewis was given leadership of the western expedition on February 28, 1803, he offered Clark the position of co-commander. Together, they explored the Louisiana Territory for more than two years, starting in present-day Missouri and ending at the Pacific Northwest coast.
The Lewis and Clark expedition began in May, 1804 and ended in 1806. Afterward, Lewis went on to become governor of the Louisiana Territory. He died on October 11, 1809 at the age of 35. Clark became a Brigadier General and governor of Missouri Territory. He died at the age of 68 on September 1, 1868.