During the late 1860s, Mountain Chief, like many other South Piegan chiefs, tried to stop trading between South Piegans and white whiskey traders. Although Mountain Chief was peaceful, he was accused of killing
John Bozeman in the spring of 1867. As a result of Bozeman and later Malcolm Clarke's deaths, the warriors in Mountain Chief's band became the target of the Second United States Cavalry on January 23, 1870, resulting in the
Marias Massacre. on January 23, 1870, and led to the death of approximately 200 Piegans from Chief Heavy Runner's Amskapi Pikuni (Blackfoot/South Piegan) band camped on the
Marias River. The massacre resulted from an incident which inflamed already tense relations between the Blackfoot Confederacy and the white settlers in Montana. All five attackers in Owl Child's party belonged to Mountain Chief's band. At the time of Owl Child's attack, Mountain Chief was the head chief of the Amskapi Pikuni. General
Philip Sheridan sent a band of cavalry led by Major Eugene Baker at
Fort Ellis to punish those involved in Clarke's death, namely Mountain Chief's band. When Baker's forces arrived along the Marias River, they approached the small camp of Gray Wolf, which was infected with smallpox (the Blackfeet Nation suffered from an epidemic of smallpox in January 1870), and the troops learned that a large band of the South Piegans was encamped down the river, which they believed was Mountain Chief's large band. This was not Mountain Chief's band, but was rather that of Chief Heavy Runner. Before the Marias Massacre, Mountain Chief and his band of South Piegan warriors, the intended target, had been warned and fled to safety in Canada before Major Eugene Baker reached them traveling downstream. The cavalry was readied to ambush the South Piegans until Heavy Runner (Blackfoot/South Piegan) came out with a safe-conduct paper, which was signed 23 days before the massacre by General Sully proving that Heavy Runner was a friend of the United States army. Despite this paper, Army scout Joe Cobell shot and killed Heavy Runner and the cavalrymen shot at the lodges and massacred the Piegans. Of the 140 people that were captured alive, all were turned loose without clothing, food, and horses and many froze to death on their return to Fort Benton. Mountain Chief had close ties to Heavy Runner's camp. Good Bear Woman, Mountain Chief's daughter, was at Heavy Runner's camp at the day of the massacre and Heavy Runner's wife was Mountain Chief's sister. General
William Tecumseh Sherman was confronted with outrage in Congress after the massacre, but he insisted that most of those killed in the incident were warriors in Mountain Chief's camp. The people of Montana and General Sherman had been given permission to attack the South Piegans if they were not within reservation boundaries, but the cavalrymen attacked the South Piegans on reservation territory that had been established in 1868. Two news articles written in February and March 1870 mentioned that Mountain Chief's son, Red Horn, was killed in the massacre. In a letter to
Philip Sheridan on March 24, 1870, Sherman stated that, "I prefer to believe that the majority of the killed at Mountain Chief's camp were warriors."
Fools Crow (1986), a novel written by
James Welch (Blackfoot/A'aninin), included the story of the Marias Massacre. == Political involvement ==