An hilarious (watch for Okla-Homer) A-Z account of how Hollywood pictures Greek history, probably extrapolating what we could be said about the depiction of Roman history as well.
More seriously, since cinema is about clichés and about a narrative basis we inherited from Aristotle and that mythology and Ancient History (is it how you call it in english? in french, we say Histoire Antique) have been serving the key plots of most tragedy playwriters from Eschylus to Shakespeare to Racine to Anouilh, it shouldn't be a surprise that Hollywood keeps the tradition high. Although, probably without the same benefits.
Once, the Spartans got me the highest grade of my Ancient History class in university at the main semester exam (="partiel" in french) and they hence got my wonderful professor, Daniel Nony, quite proud. Also, I so enjoyed to expose their decline in some lecture I gave before that. Now, they're gonna provide me with good cinematic entertainment... I hope. Frank Miller vs Daniel Nony.. that should be good match, or not. I know Nony won already with his lasting impression on me - I still remember almost 14 years later his definitive sentence: "the secret of pedagogy is the art of repetition".