The United States Congress had authorized in July 1867 the formation of an Indian Peace Commission to negotiate treaties with the Sioux, Cheyenne, Kiowa, and their allied tribes. The commission met on August 6, 1867 in St. Louis, Missouri and named the sitting Commisioner of Indian Affairs, former Congressman Nathaniel Green Taylor, as its chair. On this day, in preliminary fact finding, members met with Oglala, Brule, Yankton and Santee Sioux leaders aboard the riverboat St. John on the banks of the Missouri near Fort Thompson in present-day Buffalo County, South Dakota. Later official negotiations with prominent Plains Indian leaders resulted in the Medicine Lodge Treaty of October 1867. (By John Osborne)