Actually Gladiator got very many things wrong, from the "banning" of the Gladiator combats through to the pristine white marble of Rome and her statues.

Romans loved color and painted everything in sight. Their statues were painted to look like people, not white marble statues.

As for the Preatorians wearing purple, well only the Emperor could wear the color and Senators because it was so expensive.

I could go on but the thread seems to be closed.

Gaius Felix Fabius