In order to prepare for the role of Juan Gallardo, Tyrone Power attended a bullfight with his wife, Annabella. Because of Power's great stature as a star, he and his wife were given VIP seats in the center front of the ring. Power became violently ill witnessing the bullfight, and in order to get him out of the arena, Annabella said she was ill.
Director Rouben Mamoulian based many of the film's color schemes and designs on the works of great Spanish painters such as El Greco and Velasquez.
Twentieth Century-Fox intended to prepare "a special edition" of the picture for "circulation in South American countries." The purpose of the alternate version was to "include certain bullfighting scenes, which while they would not be acceptable in the American version, will, nevertheless, be accepted in countries where bullfighting is permitted."
Renowned bullfighter Armillita instructed Tyrone Power and other cast members in bullfighting techniques, as well as serving as Power's double in some of the bullfighting sequences shot on location.