The Louisiana Purchase sparked interest in knowing what the nation had actually purchased. President Thomas Jefferson, an advocate of exploration and scientific inquiry, had the Congress appropriate $2,500, "to send intelligent officers with ten or twelve men, to explore even to the Western ocean". They were to study, map and record information on the native people, natural history, geology, terrain, and river systems. 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 The expedition floated up the Missouri River and its larger tributaries, obtained horses from the Shoshone people to cross the Continental Divide, then floated down the Columbia River to the Pacific Ocean. On the return trip on July 3, 1806 after 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. Between the outbound and homebound portions of the trip, the expedition spent more of its time in what today is Montana than any other place.
On the return trip, Clark signed his name 25 miles (40 km) northeast of Billings, Montana. The inscription consists of his signature and the date July 25, 1806. Clark claimed he climbed the sandstone pillar now known as Pompey's Pillar and "had a most extensive view in every direction on the Northerly Side of the river". Clark named the pillar after Jean Baptiste Charbonneau, nicknamed "Pompy," the son of Sacagawea who was the Shoshone woman who had helped to guide the expedition and, along with her husband Toussaint Charbonneau had acted as an interpreter. Clark's original name for the outcropping was "Pompys Tower," but it was later changed to the current title. Clark's inscription is the only remaining physical evidence found along the route that was followed by the expedition.
In the meantime, Lewis' group met some Blackfeet Indians. Their initial meeting was cordial, but during the night, the Blackfeet tried to steal their weapons. In the ensuing struggle, two Indians 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 100 miles (160 km) in a day before they camped again.[citation needed] Lewis and Clark rejoined one another at the confluence of the Yellowstone and Missouri Rivers on August 11, 1806. After the two groups were reunited they were able to quickly return to St Louis, Missouri by floating down the Missouri River.
On the return trip, Clark signed his name 25 miles (40 km) northeast of Billings, Montana. The inscription consists of his signature and the date July 25, 1806. Clark claimed he climbed the sandstone pillar now known as Pompey's Pillar and "had a most extensive view in every direction on the Northerly Side of the river". Clark named the pillar after Jean Baptiste Charbonneau, nicknamed "Pompy," the son of Sacagawea who was the Shoshone woman who had helped to guide the expedition and, along with her husband Toussaint Charbonneau had acted as an interpreter. Clark's original name for the outcropping was "Pompys Tower," but it was later changed to the current title. Clark's inscription is the only remaining physical evidence found along the route that was followed by the expedition.
In the meantime, Lewis' group met some Blackfeet Indians. Their initial meeting was cordial, but during the night, the Blackfeet tried to steal their weapons. In the ensuing struggle, two Indians 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 100 miles (160 km) in a day before they camped again.[citation needed] Lewis and Clark rejoined one another at the confluence of the Yellowstone and Missouri Rivers on August 11, 1806. After the two groups were reunited they were able to quickly return to St Louis, Missouri by floating down the Missouri River.