Corrected entry: Pompeius and Caesar were not the only two Consuls as depicted in the series. There was a third one named Crassus as well.
Corrected entry: Brutus expresses to Caesar how sorry he is to hear that Caesar's daughter Julia has died. Brutus was actually engaged to Julia, before Caesar married her to Pompey for political reasons.
Correction: It is far from certain it was Brutus who was engaged to Julia. We know that Julia was engaged to one Quintus Servilius Caepio and that Brutus was for some time known as Quintus Servilius Caepio Brutus, having been adopted by his uncle Quintus Servilius Caepio. Some writers have stated that Caepio and Brutus are the same, but others have rejected this theory.
Corrected entry: When Julia dies at childbirth she is lying down on a bed. Roman women gave birth sitting in a chair.
Correction: She's not giving birth anymore, she's dying and saying farewell to Pompey. So they probably moved her from the chair to a bed.
Corrected entry: Pullo falls asleep while he's on guard. Soldiers who fell asleep on their guard were sentenced to death. Yet Vorenus, who is a very by-the-books man, only gets annoyed. A centurion would have executed the soldier in question.
Correction: That's a character choice, and not necessarily a plot hole. In this case, Vorenus would have no opportunity to have placed Pullo under arrest or have him tried before returning to camp, and much can have happened to make him overlook this fault in the meantime. They have won a battle together (against overwhelming odds), they have accomplished their "impossible" mission, and return as heroes with Caesar's newly-rescued grand-nephew.
Corrected entry: When Atia is having sex with the owner of the white stallion she is on top. In ancient Rome that would never happen, as whoever was on top during sex was the dominant one, and no man would consider a woman dominant over him.
Correction: A women of her stature and class would certainly be dominant over that particular man. Or if that would never be the case, maybe he just liked it that way, many people who are dominate in real life will choose to be submissive in bed. Also just because it was generally accepted that people on top where dominate, it does not mean that ever single person in the whole history of the Roman Empire believed it to be true, and followed the practice.
Correction: The series are accurate. There were only two consuls in ancient Rome, not three. Apart from that, Marcus Licinius Crassus died in 53 BC and the series start somewhere after that.