Roman republican legionary at Carrhae by Amelianvs - Deviantart Rome suffered many military disasters throughout its history. Some, like Cannae and Arausio, stand out as the very worst. The battle of Teutoburg forest was probably the worst, most humiliating defeat of the Principate period (27 BC to 284 AD). In fact, the battle of Cannae in the Punic wars is one of the most studied battles in history. The formations and tactics can be roughly imitated with line infantry, tanks and other military means. It is standard curriculum in most military colleges today. The battle of Carrhae has received far less attention. It deserves more. Rome had almost reached its territorial zenith by the end of the reign of Augustus. Up until Trajan, the empire expanded no further. Rome was far more aggressive during the republican era than in the Principate. Crassus, the Roman leader at Carrhae, was very much part of the expansionist Republica...