King Arthur: Everything
The movie is adapted from the myth, though that doesn’t give you a pass regarding credibility! Let’s just say that modern shoes have no reason to be in any depiction of the 5th century. That aside, the soldiers’ armor plates were far too heavy for battle!
Zulu: Shaved Faces
In the time of the Zulu war, it was customary for British soldiers to wear handlebar mustaches. The clean-shaven look wasn’t considered fashionable at the time at all.