Conversation so far:
When is the Blackfoot confederacy started ?
Only one of the Niitsitapi tribes are called Blackfoot or Siksika.
Does any record exist of the Blackfoots' early  history  ?
The name is said to have come from the color of the peoples' moccasins, made of leather.
They had typically dyed or painted the soles of their moccasins black.
How did the Blackfoot early society worked ?
Due to language and cultural patterns, anthropologists believe the Niitsitapi did not originate in the Great Plains of the Midwest North America.

Question: Where do they think they originate ?
Self-contained rewrite: Where do anthropologists think the Blackfoot confederacy originate ?