The Marias Massacre was a massacre of Piegan Blackfeet Native peoples which was committed by the United States Army as part of the Indian Wars. The massacre occurred on January 23, 1870, in Montana Territory. Approximately 200 Native people were killed, most of whom were women, children, and older men.

Mountain Chief was a South Piegan warrior of the Blackfoot Tribe. Mountain Chief was also called Big Brave (Omach-katsi) and adopted the name Frank Mountain Chief. Mountain Chief was involved in the 1870 Marias Massacre, signed the Treaty of Fort Laramie in 1868, and worked with anthropologist Frances Densmore to interpret folksong recordings.