Robert Aldrich's first Western.
Shot in 30 days.
There really was a renegade Apache warrior called Massai, who was a bloodthirsty killer renowned for stealing, raping and murdering. He did indeed escape from a prison train bound for Florida and made his way back to his homeland. It is, however, doubtful that he was six feet tall and had blue eyes like Burt Lancaster.
United Artists pressured director Robert Aldrich into shooting a more optimistic ending in the final days of shooting. Aldrich reluctantly agreed and was dismayed when the film was released with this alternate ending. He later concluded that "if you shoot two endings, they will always use the other one, never yours".