Conversation so far:
What was the earliest record of the Arapaho?
Around 3,000 years ago, the ancestral Arapaho-speaking people (Heeteinono'eino' ) lived in the western Great Lakes region along the Red River Valley.
Who was the chief of the tribe?
CANNOTANSWER.
How many Arapaho were there?
CANNOTANSWER.
What can you tell me about the tribe?
The ancestors of the Arapaho people entered the Great Plains from the western Great Lakes region sometime before 1700.
What made them enter a new territory?
During their early history on the plains, the Arapaho lived on the northern plains from the South Saskatchewan River in Canada south to Montana, Wyoming, and western South Dakota.

Question: What did the Arapaho do?
Self-contained rewrite: What did the Arapaho do?