Sitting Bull did not agree to the treaty. He told the Jesuit missionary, Pierre Jean De Smet, who sought him out on behalf of the government: "I wish all to know that I do not propose to sell any part of my country." He continued his hit-and-run attacks on forts in the upper Missouri area throughout the late 1860s and early 1870s. The events of 1866–1868 mark a historically debated period of Sitting Bull's life. According to historian Stanley Vestal, who conducted interviews with surviving Hunkpapa in 1930, Sitting Bull was made "Supreme Chief of the whole Sioux Nation" at this time.
Sitting Bull foreshadowing of a major victory in which a large number of soldiers would be killed. About three weeks later, the confederated Lakota tribes with the Northern Cheyenne defeated the 7th Cavalry under Lt. Col. George Armstrong Custer on June 25, 1876, annihilating Custer's battalion and seeming to bear out Sitting Bull's prophetic vision. Sitting Bull's leadership inspired his people to a major victory. In response, the US government sent thousands more soldiers to the area, forcing many of the Lakotas to surrender over the next year. But Sitting Bull refused to surrender, and in May 1877 he led his band