After the success of "The Fistful of Twilight", the upper-level director of the United American Film Company decided to continue to sign a contract with the screenwriter Luciano Vincenzoni to prepare the next film. At that time Vincenzoni, producer Erberto Grimodi, and director Sergio Leon had no idea about the new film. Later Vincenzoni proposed the idea of letting the three protagonists look for treasures during the American Civil War.
As a history lover with a unique perspective, Leon hopes to show the absurdity of the American Civil War through the film's story. He said: "I know that 120,000 people died in the Confederate prison in Andersonville, but the Federal Military Prison in the North Little is known, what you hear is always the shameful deeds of the defeated side, but the ugly deeds of the defeated side are kept secret.” In the film, the Beitville Prison where Burundi and Tuco were imprisoned was designed based on Andersonville’s steel sculptures. And many of the shots are inspired by the archive photos of photographer Matthew Brady.
Although Leon had incorporated Vincenzoni’s ideas into the script of the film, Vincenzoni still recommended the comedy screenwriter partners Aignore Incrusi and Furio Scarpelli to participate in writing the script. People are extremely disgusted with joining, he said: "I can't use anything they write, this is the worst scam in my life!" In fact, the final script of the script only adopted one sentence from the two.
Vincenzoni completed the script of the film in just 11 days, but due to tensions with Leon, Vincenzoni quickly decided to withdraw. In order to persuade Clint Eastwood to continue to star in the film, Leon and his wife specially went to California to lobby. Two days later, Eastwood agreed to play the lead, but the pay was as high as $250,000 plus 10% of the box office profit in North America. Although Leon was dissatisfied, he still reluctantly signed. Charles Bronson was the first candidate to play "Angel Eyes", but he had no time to get out because of the signing of "The Twelve Kings". In desperation, Leon chose Lee Van Kerry, who had appeared in "The Dusk of Twilight". husband. In addition, Leon originally wanted Gion Maria Volonte to play Tuco, but considering that this role requires an actor with a talent for comedy, Leon finally chose Eric Wallach, who has appeared in "Western Development".
