Factual error: Near the end of the movie, the prisoners are on the front of the locomotive with the German officer. The colonel is in the cab with the engineer and says "10 miles an hour, no more." Germans use metric - so the speed should've been given in kilometers per hour.
Factual error: Fakrash is a genie who served under King Solomon and he himself says that he's been imprisoned for 3'000 years. Yet the whole aesthetics of his clothes, decoration, architecture is the stereotypical Arabian Nights one, which would be several centuries posterior to his times and almost as foreign to him as the present day one.
Factual error: In reality, Commodus did not die in the arena - he was strangled in his apartments in 192 A.D. by an athlete who was hired by a group of Senators conspiring against him.
Factual error: The radio Walter uses on the island has no apparent power source; we never see either batteries or a hand-cranked generator.
Factual error: Ma Tatum, while bemoaning Pappy's misfortune, sits herself on a burlap bag marked "Mash". Mash, the basic component of moonshine, is a semi-liquid, and couldn't be stored in a burlap bag.
Factual error: At the start of the excommunication scene, the monks are chanting Dies Irae, a thirteenth century Catholic poem, but St. Thomas Becket died in 1170, almost a century before the poem was written.