In 1803 the United States purchased from France a huge area known as Louisiana which gave the U.S. twice as much territory as it had previously owned. Much of it was unexplored, however, and President Jefferson ordered Captain Meriwether Lewis and Lieutenant William Clark to explore this ‘wild’ western area as thoroughly as possible. They set off up the Missouri River in May 1804, leading an expedition of forty-five people, and wintered in an Indian village. Starting out again in the spring, they surveyed and charted rivers as they went, as well as hills and other landmarks, and made notes on the location and customs of the Indian tribes. By July they had reached the Rocky Mountains, and their difficulties began. Food ran short and the expedition had to exist on dried fish, roots and berries. In November they sighted the Pacific. On the return journey Lewis and Clark split up, traveling by different routes to explore further the mysterious and hitherto unknown ‘Far West’.