At the time of discovery, these Indians resided east of the Rocky Mountains in what is now Montana, and Alberta, Canada, and were grouped into three tribes: Blackfoot, Blood, and Piegan. The Piegan were the largest and dominant tribe, but all were in the habit of speaking of themselves as Blackfoot. How this name originated is not known, though there is a story that it was given them by other Indians because their moccasins were always stained with the black loam of the rich prairies of Alberta.