Hercules and the Princess of Troy (1965)

Superstrong hero Hercules, aided by young Ulysses and scientific wit Diogenes, journeys to Troy, where the city's virgins are being sacrificed to a horrible sea monster. When Princess Diana, heir to the Trojan throne currently being held by her evil uncle Petra, is selected to become the sea monster's next victim, Hercules must battle the monster - and Petra's warriors - in order to save her.