Historically Inaccurate.
While I liked the general idea of the show they got the general history so blatantly wrong that it seriously detracted from the show.
If your going to make a historical movie at least get the basics right!
Lets start with Season 1 / Episode 1 scene 1, The Roman Centurion rides into the village to announce the taxes. And these are just ridiculous mistakes.
1) All the riders have saddles with stirrups. This technically wouldn't be a problem if they didn't focus on the dam things. The stirrup was not used by Rome. In fact it wasn't even used in western Europe until after the collapse of the Western Roman Empire.
2) The Centurion is wearing the wrong helmet. I only call him that because he is wearing an infantry helmet. The equivalent of a Centurion in the Roman Cavalry was a Decurion. The crest on a Decurions helmet went front to back not side to side.
3) He is carrying a gladius and not a spatha. The gladius is an infantry sword. The spatha was specifically for the cavalry because it had a longer blade.
4) The cavalry squadron is carrying a Legions Eagle. There are so many problems with this I don't even know where to start.