the early 1790s, due to his driving interest to secure a route for the U.S. to trade interests on the Pacific coast. Jefferson tapped his personal secretary, Meriwether Lewis, to lead the expedition, and Lewis recruited William Clark, an experienced soldier and frontiersman who became an equal co-leader of the Lewis and Clark Expedition. They were to study, map and record information on the native people, natural history, geology, terrain, and river systems. The expedition floated up the Missouri River, making winter camp near the Mandan villages, east of the present border of Montana and North Dakota. The following spring, the Corps of Discovery ascended to the headwaters of the Missouri River, obtained horses from the Shoshone people to cross the Continental Divide, eventually floating down the Columbia River to the Pacific Ocean. On the return trip heading east through present-day Montana, in July 1806, after again crossing the Continental Divide, the Corps split into two groups so Lewis could explore and map the Marias River and Clark could do the same on the Yellowstone River. While proceeding down the Yellowstone, Clark signed his name northeast of modern-day Billings. The inscription consists of his signature and the date July 25, 1806. Clark named the pillar after Jean Baptiste Charbonneau, nicknamed "Pompy", the son of Sacagawea, a Shoshone woman who had helped to guide the expedition and, along with her husband Toussaint Charbonneau, had acted as an interpreter. Clark's inscription is the only remaining physical evidence found along the route that was followed by the expedition. In the meantime, Lewis' group descending the Marias met a small party of Piegan Blackfeet. Their initial meeting was cordial, but during the night, the Blackfeet tried to steal their weapons. In the ensuing struggle, two men were killed, the only native deaths attributable to the expedition. To prevent further bloodshed, the group of four—Lewis, Drouillard, and the two Field brothers—fled over in a day before they camped again. Lewis's and Clark's separate parties rejoined one another at the confluence of the Yellowstone and Missouri rivers on August 12, 1806. Thus reunited, and heading downstream, they were able to quickly return to St. Louis. During the trip, the expedition spent more of its time in what today is Montana than any other place. First settlements St. Mary's Mission was the first permanent European settlement in Montana. Through interactions with Iroquois between 1812 and 1820, the