After directing "The Good, the Bad and the Ugly", Leone decided to retire from Westerns and desired to produce his film based on "The Hoods", which eventually became "Once Upon a Time in America", but Leone accepted an offer from Paramount Pictures to provide access to Henry Fonda and to use a budget to produce another Western film. He recruited Bertolucci and Argento to devise the plot of the film in 1966, researching other Western films in the process. After Clint Eastwood turned down an offer to play the movie's protagonist, Bronson was offered the role. During production, Leone recruited Donati to rewrite the script due to concerns over time limitations.