The Assiniboine Tribe was a hunting-gathering people whose range encompassed the prairie lands between the Saskatchewan River in the north to the Missouri River in the south. "The Stone Boilers," or "People of the White Clay," as they called themselves, were an early offshoot of the Sioux as their dialect confirms. They were relatively horse poor, which contributed to their daring as cunning horse thieves, especially against the avowed enemy, the Blackfeet Nation. Their surprise winter horse-stealing raids were legendary.