Clash of the Titans, 1981
The Story: Perseus tries to save his bride from a giant sea monster by turning it to stone using the decapitated head of Medusa. His backup? A flying horse and a friendly owl.
Gratuitous Skin: Medusa is unappealingly topless during the scene in which Harry Hamlin uses his sword to make her permanently topless.
Historical Accuracy: The Perseus myth was passed down through the oral and literary tradition for millennia before Hollywood tore it apart for creative reasons.
The Moral: Krakens will be Krakens.
The Story: A power-crazed sexual deviant named Gaius Germanicus Caesar takes the throne and proceeds to behave rather badly, murdering people, forcing senators' wives into prostitution, and (because the worst ones always do) trying to invade England.
Gratuitous Skin: Other than the graphic oral sex, incest, necrophilia, and rape, it's a pretty clean movie.
Historical Accuracy: Caligula was definitely crazy, but he probably wasn't Malcolm McDowell crazy.
The Moral: Do unto others as you would have them do unto you – especially when you're at an orgy.
The Story: Pseudolous the slave tries to earn his freedom by getting his young, dull master Hero in bed with a local courtesan who has just been sold to a legionnaire. This requires a lot of singing.
Gratuitous Skin: What the musical lacks in violence, it makes up for in cleavage. Plenty of boys spent the sixties re-watching the sex scene and none of them knows any lyrics.
Historical Accuracy: Inspired by the works of early satirists, the play is – probable for budget reason – likely the most realistic film on this list. That said, Romans probably didn't lean so hard on schtick.
The Moral: Lying (and casting Zero Mostel) is always the right decision.