William Clark was an American explorer who along with Meriwether Lewis led an epic expedition to the Pacific Northwest. Named after these great explorers, the Lewis and Clark Expedition was undertaken following the Louisiana Purchase and aimed at claimed the Pacific Northwest for the United States before any of the European powers did. Before being selected for the expedition Clark served in a militia. Born into a large family of tobacco planters in Virginia, he enjoyed an adventurous childhood filled with fox hunts, cockfights, and shooting tournaments. His five older brothers fought in the American Revolutionary War but William was too young at that time. On growing up he joined a volunteer militia force under Major John Hardin to fight in the American Indian conflicts of the Ohio frontier. He then entered the U.S. Army and commanded a company of riflemen at the Battle of Fallen Timbers, playing an important role in the decisive U.S. victory that brought the Northwest Indian War to an end. He eventually retired from the army due to poor health. After a few years he was invited by his friend Meriwether Lewis to join him on an expedition to the Pacific Northwest. The expedition which took several long months to complete was a resounding success which catapulted both Clark and Lewis to the status of legendary explorers.