Nationally:

The Boston Braves adopted their team name in 1912. The Cleveland Indians took theirs in 1915. Scores of high schools and colleges across the country assumed these and other Indian team names after that through the 1920s and 1930s, even as so-called “civilization regulations” forbade Native Americans to speak their languages, practice their religions or leave their reservations.

“This meant real American Indians could not openly perform ceremonial dance at a time when painted-up pretend ones could prance on sidelines.

The Indian population had collapsed from several million to about 250,000, largely confined to reservations, entirely at the mercy of the federal government.”

“Congress granted the Secretary of the Interior supervision over American Indian affairs in the late 19th Century. The Department of the Interior imposed a series of rules that essentially outlawed Native American culture. The department also created quasi-criminal laws and codes of conduct — offenses and penalties that applied only to American Indians — complete with kangaroo courts and provisional prisons, all of it designed to “civilize” Native Americans.”

Then there were the boarding schools, where Indian children were taken with the motto: Kill the Indian, Save the Man.

“All of this was taking place outside the view of the average American,” Gover says. “At that time, someone living in Philadelphia — or, more tellingly, in Cleveland or Boston — might conclude there are no Indians anymore. They are gone. And, in fact, that was the objective of federal policy. … So there were a lot of very powerful forces at work to deny Native American people of agency over their own identities and their very lives. And that’s when the mascots emerged.”

(Excerpts taken from a USA today interview with Kevin Grover, director of the Smithsonian Institution’s National Museum of the American Indian and a citizen of the Pawnee Tribe of Oklahoma. https://www.usatoday.com/story/sports/2016/08/24/real-history-native-american-team-names/89259596/  )