On the evening of August 18, 1805, camped about 35 miles southeast of this area, Meriwether Lewis spent his thirty-first birthday in introspection after an emotionally turbulent week in which the Corps of Discovery, after several false starts, had finally established positive relations with the Lemhi Shoshoni. For months the expedition had anticipated that moment, having welcomed Sacajawea largely because as a Shoshoni she might help them obtain the horses they needed to cross the Rockies before winter. After a night of celebration, many members of the Corps departed with most of the Shoshoni for the tribe's main camp and to explore routes for the next stage of the journey, leaving Lewis in unusual tranquility and comparative solitude. In his journal he regretted the hours he believed he had wasted, lamented how little he had yet done to further human happiness or advance knowledge for future generations, and resolved to redouble his efforts and live for mankind rather than for himself. Lewis died on October 11, 1809, a little more than four years later; in his 36 years he had been a military leader, a trusted aide to President Thomas Jefferson, one of the most experienced and accomplished white explorers in American history, and America's first great travel writer.