The Battle of Carrhae was an important battle between the Roman Republic and the Parthian Empire. The battle took place in 53 BC, near the town of Carrhae. The Roman General Marcus Licinius Crassus won a decisive victory over the Parthian General Surena and was the opening battle in the Romano-Parthian war.
Political background in Rome
In March and April 56 BC, meetings were held in Ravenna and Luca, in Cisalpine Gaul, to reaffirm the weakening alliance formed four years earlier by Julius Caesar, Pompey Magnus and Marcus Crassus. The triumvirate aimed to expand their faction's power through traditional means: military commands, placing political allies in office, and advancing legislation to promote their interests. Legislation passed by the tribune Trebonius granted extended proconsulships of five years, matching that of Caesar in Gaul, to Pompey and Crassus. The Spanish provinces would go to Pompey, while Crassus would govern Syria, with the transparent intention of going to war with Parthia. Some Romans objected to a war against Parthia. Crassus left Rome on November 14, 55 BC. His son, Publius, joined him in Syria during the winter of 54–53 BC, bringing with him the thousand Celtic cavalry troopers from Gaul.
Build up to war
Crassus arrived in Syria in late 55 BC and immediately set about using his immense wealth to raise an army. He raised seven legions (35,000 men), eight cohorts of auxiliaries (4000 men), and 4000 cavalry, including the 1000 Gallic horsemen brought to Syria by Publius. The Armenian king Artavasdes advised Crassus to take a route through Armenia to avoid the desert and offered him reinforcements of 16,000 cavalry and 30,000 infantry. Crassus refused the offer and decided to take the direct route through Mesopotamia, and capture the great cities in the region.
The Parthian king, Orodes II, in response to Crassus' preparations for war, divided his army and he took most of his soldiers, mostly infantry and a small amount of cavalry, to punish the Armenians and sent the rest of his forces, 9000 mounted archers and 1000 cataphracts under the command of the General Surena to hold off Crassus' army until Orodes could return from Armenia with the rest of the army.
Crassus crossed the Euthrates and advanced into Mesopotamia, where he encountered Surena's army near the town of Carrhae.
After being informed of the presence of the Parthian army, Crassus deployed his army in the traditional Roman fashion, with infantry forming the center and cavalry on the wings. This formation would allow his forces to maneuver, but at the risk of being outflanked. The Roman forces advanced and came to a stream. Crassus' generals advised him to make camp, and attack the next morning in order to give his men a chance to rest. Publius, however, was eager to fight and managed to convince Crassus to confront the Parthians immediately.
The Parthians went to great lengths to intimidate the Romans. First they beat a great number of hollow drums and the Roman troops were unsettled by the loud and cacophonous noise. Surena then ordered his cataphracts to cover their armor in cloths and advance. When they were within sight of the Romans, they simultaneously dropped the cloths, revealing their shining armor. The sight was designed to intimidate the Romans, but Surena was impressed by the lack of effect it had. Though he had originally planned to shatter the Roman lines with a charge by his cataphracts, he judged that this would not be enough to break them at this point. Thus, he sent his horse archers to surround the Roman square. Crassus sent his skirmishers to drive the horse archers off, but they were driven back by the latter's arrows. The horse archers then engaged the legionaries. The legionaries were protected by their large shields and armor, but these could not cover the entire body. Therefore the majority of wounds inflicted were nonfatal hits to exposed limbs. The Romans repeatedly advanced towards the Parthians to attempt to engage in close-quarters fighting, but the horse archers were always able to retreat safely, loosing Parthian shots as they withdrew. The legionaries then formed the testudo formation, in which they locked their shields together to present a nearly impenetrable front to missiles. However, this formation severely restricted their ability to fight in melee combat. The Parthian cataphracts exploited this weakness and repeatedly charged the Roman line, causing panic and inflicting heavy casualties. When the Romans abandoned the formation, the cataphracts withdrew and the horse archers resumed shooting.
Crassus now hoped that his legionaries could hold out until the Parthians ran out of arrows. However, Surena used thousands of camels to resupply his archers. Upon realizing this, Crassus dispatched his son Publius with his 1000 Gallic cavalry to advance and provoke an attack from the horse archers. The Gauls were immediately surrounded and attacked by the mounted archers. Once they were engaged, their position was fixed and they were vulnerable to an approach by the Roman legionaries. Crassus ordered his troops to advance and envelope the horse-archers. The Parthians were now forced into close-quartered combat against the legionaries and suffered heavily for it, for they were unsuited for such combat. The Parthian cavalry's will eventually broke and panic spread, many of the horse archers being killed as they tried to escape. Surena was eventually slain along with his bodyguards, and the remaining Parthians broke and fled. Overall the Roman army had achieved a complete victory. Roman casualties amounted to about 200 killed and 1000 wounded, while the Parthians suffered over 9400 killed.
The Battle of Carrhae was a decisive Roman victory and marked the beginning of the end of the Parthian empire. Crassus advanced further into Mesopotamia, defeating Orodes and the rest of the Parthian Army before sacking Ctesiphon later that year. Crassus installed an exiled Parthian prince, Mithridates III, as king of Parthia and made the kingdom into a Roman client state. Crassus would however never return to Rome as he contrated a fever and died in Antioch in October 51 BC. His death permanently unraveled the alliance between Caesar and Pompey. Within two years of Crassus' death, Caesar would cross the Rubicon and begin a civil war against Pompey and the legitimate government of the Republic.