Carlo Rambaldi was the responsible for the Cyclops special effects. He received credit as "creazione animate", which translates to "animated creation".
To increase their chances in the lucrative American market, the Italian title was changed to what was translated into English as "The Giants of Thessaly." The previous year, a Steve Reeves film had been a success in the US when its English-language title was changed to "The Giant of Marathon." It was assumed that most Americans would not be familiar with the term "Argonaut."
Final film of Lilia Landi.
Italian censorship visa #33588 issued December 6, 1960.
Final film of Alice Clements.