From Wikipedia:

Chief Washakie (c. 1798 – February 20, 1900) was a renowned warrior first mentioned in 1840 in the written record of the American fur trapper, Osborne Russell. In 1851, at the urging of trapper Jim Bridger, Washakie led a band of Shoshones to the council meetings of the Treaty of Fort Laramie (1851). Essentially from that time until his death, he was considered the head of the Eastern Shoshones by the representatives of the United States government.