The hawk featured in the movie went under the name Spike II and 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. Several different hawks were used. One to sit on Rutger Hauer's arm and another for the flying scenes. A third proved to be mostly unusable, as it enjoyed Hauers company so much that it would ruffle it feathers when seated on his arm, making it look more like a chicken than a stately hawk.
In one scene, Navarre tells Philippe 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, Rutger Hauer (Navarre) slapped the horse too hard and it took off over the hill and off into the horizon. The horse was too powerful for Matthew Broderick to stop, so all everyone could do was sit and wait for him to come back.
Richard Donner originally wanted to cast Rutger Hauer as the evil captain of the guard while casting a younger actor, 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.
The breed of horse that Navarre rides is a Friesian stallion that originated in the Netherlands, Rutger Hauer's native country. The breed was popular among medieval knights. The most prominently used horse was a 19 year old stallion called Othello.
In the Bishop's garden, he is seen hand-feeding a dancing woman (played by Constume Designer Nanà Cecchi). The pattern on the sleeves of her gown is drawn from the plumage of a hawk, and she employs bird-like motions in her dancing.
Warner Brothers falsely marketed the movie as being based on a true medieval legend. Edward Khmara took the issue to the Writers Guild Association and was awarded a cash settlement from Warners, but the medieval legend claim wasn't dropped.
Some movie posters for this film featured a long text preamble that read: "A crafty young pickpocket stole his way out of a tyrant's dungeon and plunged into an adventure beyond even his own wildest imaginings. And the strangest notion of all was that he was about to become a hero."
The relationship between Navarre and Gaston was considered a possible influence behind the relationship between the characters of Kanan Jarrus and Ezra Bridger in Star Wars: Rebels (2014). In that series, Ezra Bridger, a con artist and small time thief is taken on and trained as a Jedi by Jedi Knight Kanan Jarrus.
John Wood plays a corrupt Catholic bishop. In Lady Jane (1986), he plays John Dudley, Duke of Northumberland. Dudley schemed to place his daughter-in-law, Lady Jane Grey, on the English throne for 9 days in an effort to keep Mary I - a devout Catholic - from ruling the country.
Based on geographical, historical and astronomical facts, the film's action presumably takes place in 1386, in Italy, 36 years after the Black Death. Yet, although a real total eclipse did occur across southern France into Italy on January 1, 1386, in-film dialogue - specifically, references to the Crusades and none concerning the Black Death - and film marketing indicate that the movie takes place during the 13th century (1200s).
A goof and trivium: when Navarre kills the Bishop by impaling him with the greatsword, he drives the sword all the way up to the crossguard/quillons, driving the blade's (projecting) lugs through the body, which would be extraordinarily improbable, if not actually impossible.