French actor Alain Delon requested to make this film after enjoying his role in the swashbuckler The Black Tulip in 1964.
The final sword duel was inspired by the 1952 swashbuckler Scaramouche.
One of the first modern Western movies to be shown in China in 1978, after the Cultural Revolution. Over 70,000,000 moviegoers watched it.
During the shooting of the movie, in Spain, Alain Delon met Leon Degrelle, the former Belgian Nazi leader, who drove the Foreign SS Legion during WW2. Leon Degrelle ran away after the war, certainly to escape from a possible trial.
The last feature film of Stanley Baker.