Spike II, the hawk featured in this movie, worked in the Universal Bird Show until 2000, when she was transfered to the National Audubon society and became an Audubon Ambassador until she died in May 2007. Another hawk was used for flying scenes, and another to sit on Rutger Hauer's arm. One enjoyed Hauer's company so much it would ruffle its feathers when seated on his arm, making it look more like a chicken.
In one scene, Captain Etienne Navarre (Rutger Hauer) tells Philippe Gaston to ride his horse to Imperius' castle and slaps the horse's rear to make it ride. However, the first time the scene was filmed, Hauer slapped the horse too hard and it took off over the hill and off into the horizon. The horse was too powerful for Broderick to stop, so all everyone could do was sit and wait for him to come back.
Three of the castles used for this movie were owned by Italian movie director Luchino Visconti and his family.
Rutger Hauer has said that one of his proudest moments in this movie was being able to flip the dagger in his hand during the climactic fight without looking at it.
Producer and director Richard Donner originally wanted to cast Rutger Hauer as the Captain of the Guard, and Kurt Russell as Navarre. Hauer wasn't interested in that role, but expressed interest in playing Navarre. When Russell dropped out a few days before principal photography began, the part was handed to Hauer.