Sitting Bull
American historian and biographer Stanley Vestal states in his biography "Sitting Bull: Champion of the Sioux" that Collins "knew him better than almost any other white person at the agency." Her close relationship with Sitting Bull, along with her quest for peaceful cooperation between both Natives and the expanding white settlements, led her to ask Sitting Bull to stop encouraging the Ghost Dance, which was believed to have contributed to Lakota resistance. This dance was seen as a threat by U.S. Army troops and policemen sent to the Dakota region, who misinterpreted the dance as a prelude to armed attack. Sitting Bull and his tribe persisted, and on December 15, 1890, Sitting Bull was arrested, and subsequently shot and killed in the ensuing mayhem. Following the Wounded Knee Massacre later that month, the practice of Ghost Dancing was outlawed.