Sergio Leone was one of the second unit directors. He had a more rewarding experience on this American film since he was able to communicate directly with the director, Robert Wise, since both of them could speak French.
In 2005 members of the Max Steiner Music Society were granted access to the Warner Brothers archives to research the music score. Amongst the documents unearthed were the original schedules for the English dubbing which revealed that Jacques Sernas had been dubbed by Geoffrey Toone, not by Edmund Purdom as previously speculated. The confusion arose because Toone and Purdom had strikingly similar voices. Toone was brought into the dubbing booth on 22 March 1955 and recording continued in projection room #14 up to 2 May 1955 with Barbra Fuller apparently dubbing Brigitte Bardot and Glenn Langan narrating. Mysteriously missing from the vaults was the identity of the voice actress chosen for Helen herself, although separate researches (unconfirmed) indicate that Joan Croydon dubbed Rossana Podesta.
In Homer's "The Odyssey", after the siege of Troy, Ulysses would then embark on a perilous journey home. Among those dangers was encountering a Cyclops. In this movie, Ulysses is played by Torin Thatcher, who would later co-star in The 7th Voyage of Sinbad (1958) and he would encounter a Cyclops in that film.
On kissing Helen, Paris tells her "make me immortal with a kiss." He is echoing the famous lines from Christopher Marlow's play Doctor Faustus, in which Faustus, on seeing a vision of Helen of Troy, says "Was this the face that launched a thousand ships, And burnt the topless towers of Ilium? Sweet Helen, make me immortal with a kiss."
Italian reference sources "Filmlexicon" and "Colonna Sonora" both credit the music score to Roman Vlad. The most likely explanation is that the Italian musicians' union insisted an Italian member (Vlad was affiliated to SIAE) be paid to write a score, even if it was never used.
The city of Troy built for the movie is modeled after the Palace of Knossos in Crete, with red painted Minoan columns and carved stone bull's horn motifs visible everywhere. While Troy and Knossos were roughly contemporaneous, they were nowhere near each other either geographically or culturally.
The trivia item below may give away important plot points.
It must be noted that since this version of the Trojan war is an Italian production therefore the names of the gods and some of the characters are from the Roman mythology of the story rather than Greek. Hence Ulysses is Roman name for Odysseus. For reference see the movie Ulysses starring Kirk Douglas which came out a couple years before.