Have you ever watched The Gladiator? How many of them were black? They were slaves.

Do you know how many slaves were black in the Roman empire? More than had American accents I assure you.

None of them spoke English either.

More times than I can count, bubba. And if you can't differentiate between a producer making a movie in English because its main audience is English speaking and producing a movie that is either: (1) accurate historically; or (2) true to its original story -- than I can't help you, bud.