premise: Chief Crazy Horse is a 1955 American CinemaScope Technicolor Western film directed by George Sherman starring Victor Mature, Suzan Ball and John Lund. The film is a fictionalized biography of the Lakota Sioux Chief Crazy Horse. It was also known as "Valley of Fury".
hypothesis: Chief Crazy Horse was not a real person
reason: Chief Crazy Horse was a real person, but the events of this movie are fictional