Ability over Appearance: Nigel Green is certainly not what the popular image of Hercules was at the time, lacking the stereotypical Heroic Build and muscleman physique.
California Doubling: Several scenes were filmed in Italy instead of Greece, Aegean Sea islands and the Black Sea (the way to Colchis, modern-day Georgia). Amusingly, the temple of Hera in Paestum near Salerno was used as a temple of Zeus.
Cowboy Be Bop At His Computer: Some magazines named Mario Nascimbene as the composer of the film rather than Bernard Herrmann because he was who the filmmakers were considering if the latter turned it down. He would eventually do the score for another film featuring Stop Motion creatures by Ray Harryhausen, One Million Years B.C..
Divorced Installment: Presumably in order to capitalize on the success of The 7th Voyage of Sinbad, Ray Harryhausen originally conceived of the film as Sinbad in the Age of Muses. The story would still have been set in ancient Greece and would have involved Sinbad joining Jason in the search for the Golden Fleece.
Hostility on the Set: John Cairney (Hylas) and Nigel Green (Hercules) didn't actually get along at all during filming. Green would accuse Cairney of being very "effeminate" (Cairney was actually married at the time!) causing Cairney no end of trouble. The last scene they filmed together was the scene where Hercules and Hylas enter the treasure chamber, hidden in the plinth of the mighty Talos. The lighting used to give the treasure its sparkling effect was very severe, and the following day, the actors began losing their vision. Frighteningly, both actors became temporarily blind and were hospitalised together in the same room for two weeks with their eyes bandaged. Fortunately their sight returned after their stay in hospital. During those two weeks of confinement with each other, they found they had a lot in common, and soon became fast friends. They remained good friends until the day Nigel Green died in 1972.
One-Hit Wonder: This was one of only two major roles for Todd Armstrong, and he's still only known for playing Jason here. The other was in the World War II film King Rat.
Other creatures considered to appear would have included the twin monsters Scylla and Charybdis, the three-headed dog Cerberus and Jason's centaur mentor Chiron.
Working Title: The film was going to be titled Jason and the Golden Fleece and many pre-release prints had this title card, before it was changed to Jason and the Argonauts.
2000 Miniseries
Awesome, Dear Boy: Jolene Blalock had been a successful model branching into acting, and at the time was turning down many offers to do generic Ms. Fanservice roles in indie films. She took the role of Medea for this reason, saying that Frank Langella playing her father sealed the deal.
Completely Different Title: The title in Brazil was "A Vingança do Gladiador", which translated into English means "The Vengeance of the Gladiator", although there are no gladiators in this movie.
Friendship on the Set: Jolene Blalock befriended Dennis Hopper for the week she was filming with him in the latter half of the miniseries.
Lying Creator: Some versions of the DVD advertise "over four hours of epic adventure." With the two episodes edited together, the miniseries runs at only three hours.
Making Use of the Twin: Jason London's twin Jeremy (also an actor) doubled for him in parts.
Prop Recycling: The ship used for the Argo had previously been built for Hallmark's The Odyssey miniseries three years earlier.
