The Black Shield of Falworth, in which Tony Curtis plays an English aristocrat. “Dese are da lands of my fadda, and yondah lies his castle!”
And then there is The Vikings, in which Tony Curtis and Kirk Douglas play Hollywood’s finest examples of Jewish Vikings.
In the Kirk Douglas version of Spartacus, the slaves spoke in US accents, and the aristocratic Romans spoke in RP accents.
In films from the 1930s to the 1950s, they often just used the actors’ normal accents. Quite a few “B” movies have European characters speaking in American accents. And even some “A” pictures. In the Elizabeth Taylor/Richard Burton version of Cleopatra, a lot of the Roman characters use UK accents,and a lot of the Egyptian characters use US accents, but they are not consistent. It was more a matter of which actor was cast in which role.
I once heard a guy do a speech from A Midsummer Night’s Dream twice, once in RP, then again in what he claimed was Shakespeare’s actual accent. (I think he said it was a Warwickshire dialect. It sounded sort of like a Scottish or Irish brogue.) In the brogue, it “flowed” better, and actually much easier to understand.
As I understand it, Latin does not have articles (“a”, “an”, “the”). Since the story is shown from the point of view of the slaves, it gives an impression of being a stranger in an alien land, surrounded by people who talk strangely.