Blackfoot Confederacy. The Blackfoot Confederacy, Niitsitapi or Siksikaitsitapi is a historic collective name for linguistically related groups that make up the Blackfoot or Blackfeet people: The Siksika, the Kainai or Kainah, and two sections of the Piikani, the Northern Piikani and the Southern Piikani. Broader definitions include groups, like the Tsúùtínà and A'aninin, spoke quite different languages but allied or joined with the Blackfoot Confederacy as well. Historically, the member peoples of the Confederacy were nomadic bison hunters and trout fishermen, who ranged across large areas of the northern Great Plains of western North America, specifically the semi-arid shortgrass prairie ecological region. They followed the bison herds as they migrated between what are now the United States and Canada, as far north as the Bow River. In the first half of the 18th century, they acquired horses and firearms from white traders and their Cree and Assiniboine go-betweens. The Blackfoot used these to expand their territory at the expense of neighboring tribes. Today, three First Nation band governments reside in Canada in the provinces of Saskatchewan, Alberta, and British Columbia, and the Blackfeet Tribe of the Blackfeet Indian Reservation is a federally recognized Native American tribe in Montana, United States. Originally the Blackfoot/Plains Confederacy consisted of three peoples based on kinship and dialect, but all speaking the common language of Blackfoot, one of the Algonquian languages family. The three were the Piikáni, the Káínaa, and the Siksikáwa. They later allied with the unrelated Tsuu T'ina, who became merged into the Confederacy and, with the Atsina, or A'aninin. Each of these highly decentralized peoples were divided into many bands, which ranged in size from 10 to 30 lodges, or about 80 to 240 persons. The band was the basic unit of organization for hunting and defence. The largest ethnic group in the Confederacy is the Piegan, also spelled Peigan or Pikuni. Their name derives from the Blackfoot term Piikáni. They are divided into the Piikani Nation in present-day Alberta, and the South Peigan or Piegan Blackfeet in Montana, United States. A once large and mighty division of the Piegan were the Inuk'sik of southwestern Montana. Today they survive only as a clan or band of the South Peigan. The modern Kainai Nation is named for the Blackfoot-language term Káínaa, meaning Many Chief people. These were historically also called the Blood, from a Plains Cree name for the Kainai: Miko-Ew, meaning stained with blood. The common English name for the tribe is Blood or the Blood tribe. The Siksika Nation's name derives from Siksikáwa, meaning Those of like. The Siksika also call themselves Sao-kitapiiksi, meaning Plains People. The Sarcee call themselves the Tsu T'ina, meaning a great number of people. During early years of conflict, the Blackfoot called them Saahsi or Sarsi, the stubborn ones, in their language. The Sarcee are from an entirely different language family; they are part of the Athabascan or Dené language family, most of whose members are located in the Subarctic of Northern Canada. Specifically, the Sarcee are an offshoot of the Beaver people, who migrated south onto the plains sometime in the early eighteenth century. They later joined the Confederacy and essentially merged with the Pikuni. The Gros Ventre people call themselves the Haaninin, also spelled A'aninin. The French called them Gros Ventres, misinterpreting a physical sign for waterfall; and the English called them the Fall Indians, related to waterfalls in the mountains. The Blackfoot referred to them as the Piik-siik-sii-naa or Atsina, because of years of enmity. Early scholars thought the A'aninin were related to the Arapaho Nation, who inhabited the Missouri Plains and moved west to Colorado and Wyoming. They were allied with the Confederacy from circa 1793 to 1861, but came to disagreement and were enemies of it thereafter. The Confederacy occupied a large territory where they hunted and foraged; in the 19th century it was divided by the current Canada-US international border.