Factual error: When the whore is talking to Lily, she says "The first thing she should do (in her new tent) is to get the carpenter to lay some boards, or she will be saying hello to Mr. Trench Foot", referring to the medical issue related to feet in wet and unsanitary conditions. This disease of the feet was not referred to as this until World War One. (00:23:10)
Revelations - S1-E7
Factual error: During the race between the horse and the train, the horses are wearing shoes. The Native Americans had no way of forging steel to make horse shoes.
