IN 1804, MERIWETHER Lewis and William Clark began an expedition across the newly acquired Louisiana Purchase territory. These two army captains were chosen by the American president, Thomas Jefferson, to explore new land the United States had purchased from France one year earlier, and to find a direct water route across the nation. For a little over two years, Lewis and Clark led their corps through some 8,000 mi (12,800 km) of unexplored lands, acquiring scientific samples, creating maps, and conveying to the local Native Americans that an acquisition of their territory by the United States had just occurred. The idea of an expedition into the Louisiana Purchase territory began in early 1803 after approval by the U.S. Congress. Lewis, the personal secretary and friend of Jefferson, was chosen to lead the expedition. Lewis entered the army in 1794, where he served in the Frontier Army and rose to the rank of captain. He possessed quality leadership, scientific, and cartography skills, which contributed to the goals of the expedition. In June 1803, Lewis wrote a letter to his friend, Clark, expressing his desire to lead the expedition with him, as well as to recruit volunteers. Lewis had previously served under Clark during the latter half of the 1790s, and he viewed Clark as an able-bodied and highly intelligent leader. Clark accepted the proposal, and in the middle of October 1803, he met Lewis in Clarksville, in the Indiana territory. The two men began preparations and enlisted men for their new Corps of Discovery. Two months later, the crew was in St. Louis, Missouri, making final preparations for the journey. After a winter of training their corps and stocking up on goods and materials, Lewis, Clark, and the Corps of Discovery embarked on their exploration on May 14, 1804. Lewis and Clark proved to be adept at leadership, and each used individual skills to the advantage of the group. Lewis was the planner and scientist. He proved his strength and stamina when he saved himself from a fall off a cliff by wedging his knife into a crevice and breaking the fall. He cured a case of accidental poisoning through a homemade remedy. Lewis even survived an accidental gunshot wound from one of the corps members.