Publius Crassus in Aquitania, 56 BC: The Triumvir's Son Who Won Two Campaigns Before Carrhae

In 56 BC Publius Crassus, son of the triumvir, led twelve cohorts into Aquitania and beat the Sotiates, Vocates and Tarusates before dying at Carrhae.

2 October 2026 · Part of Roman Empire & Republic — a guide to 25 articles →

In the summer of 56 BC, a legate of about thirty, with twelve cohorts and a large cavalry force, marched into Aquitania, the south-western third of Gaul, and defeated the Sotiates, the Vocates and the Tarusates in a single season. His name was Publius Licinius Crassus, and three years later he would die at Carrhae beside his father, the triumvir Marcus Crassus. Because Carrhae is the part of his life everyone remembers, his Gallic service has almost vanished behind it. Yet it is the only stretch of his career for which we have a detailed account of him giving orders, and Caesar's third book devotes most of eight chapters to it (BG III.20-27). The campaign appears in our record of Caesar's operations in Gaul and Britannia as the conquest of Aquitania, commanded by Crassus rather than by Caesar.

Why Caesar Sent a Young Man

Publius Crassus had come to Gaul as one of Caesar's legates, an appointment that tied Caesar to the richest man in Rome. In 58 BC, at the battle against Ariovistus, he was in command of the cavalry and saw that the Roman third line was needed; he ordered it forward, and Caesar credits that decision with restoring the day (BG I.52). In 57 BC Caesar sent him with a single legion to the Atlantic coast, and the tribes of Armorica, including the Veneti, offered submission (BG II.34). That submission was brittle: the next winter it broke over requisitioned grain, and the naval war against the Veneti followed.

For 56 BC Caesar had several fronts. He himself dealt with the Veneti and the coastal tribes, Titurius Sabinus went against the Venelli and their neighbours in Normandy, and Crassus was sent south. Caesar's stated reason is that Aquitania was large and populous, and that he wished to prevent its tribes from sending reinforcements to the rest of Gaul (BG III.11). Aquitania differed from the lands to its north: Caesar opens his work by noting that its people differed from the Celts and Belgae in language, customs and laws (BG I.1). Modern linguists generally connect the personal names on later Aquitanian inscriptions with ancestral Basque, which agrees with him.

The Sotiates: Tunnels and Devoted Followers

Crassus began with recruitment. He drew reinforcements from Tolosa (Toulouse), Carcaso (Carcassonne) and Narbo (Narbonne), the communities of the Roman province nearest to Aquitania, and brought them into Sotiates territory (BG III.20). The Sotiates met him with a large cavalry force and attacked his marching column. After a cavalry fight in which the Romans eventually prevailed, the Sotiate infantry, who had been hidden in a valley, came out and the battle was renewed. It ended in a Roman victory, and Crassus moved on their main town (BG III.20-21).

The siege showed something about the Aquitani. When Crassus advanced siege-sheds and towers against the walls, the defenders made sorties and then tried to undermine his works with tunnels, which Caesar says they were expert at because of their copper mines (BG III.21). Crassus's diligence defeated the tunnelling, according to Caesar, and the Sotiates, seeing no chance of success, asked for terms. He accepted their surrender and ordered the weapons handed over. While this was going on, the king Adiatunnus attempted a sortie from another side of the town with 600 soldurii, bound followers who, in Caesar's description, shared in all the good things of life with the man to whom they had devoted themselves and died with him if he died (BG III.22). Caesar says the sortie was driven back, and that Adiatunnus was nevertheless given the same terms as the rest.

The Vocates and Tarusates: A Spanish Army

Crassus then moved against the Vocates and Tarusates. Their reaction is the more interesting part of the campaign. They sent for help across the Pyrenees, and received men from Hispania Citerior, among them leaders who, in Caesar's words, had served under Quintus Sertorius and were thought to be experienced commanders (BG III.23). Sertorius had waged a long guerrilla war against Rome in Spain until his murder in 72 BC, and Caesar presents these veterans as men who intended to fight the Roman way, with fortified camps and cut supply lines.

That put Crassus in a difficult position. His force was smaller than the enemy's, his supply lines were exposed, and he held a council about whether to fight at once or wait (BG III.24). Caesar tells us that he judged delay would strengthen the enemy and that his own men were eager. The next day he drew up his army but found the enemy staying behind their fortifications. An assault on a well-held camp was risky. According to Caesar, Crassus therefore sent a force round the back of the enemy camp, where the fortifications were weaker, while the main body attacked the front and kept their attention (BG III.25-26). The result was a rout. Caesar says that of an enemy force of more than 50,000 drawn from the Aquitani and the Cantabri, barely a quarter survived (BG III.26). Treat that figure with caution: it is Caesar's, and ancient battle counts regularly grow with the glory of the victor.

Chronology

What the Campaign Did, and Did Not, Achieve

Caesar says that nearly all of Aquitania then sent hostages and submitted, while some remote tribes neglected to do so because the season was far advanced (BG III.27). That qualification matters. The conquest was formal rather than thorough,. Caesar does not tell us how many men Crassus lost, a silence common in his accounts of victories, so the campaign's cost cannot be measured.

Why does it matter, then? First, it shows what Caesar's legates could do alone. In the same summer Sabinus and Decimus Brutus also won independent operations, and the Aquitanian campaign is one of the clearest cases of a legate with his own army fighting a Roman-style battle against opponents who used Roman methods. Second, it shows how the Gallic War was in part a training ground. Crassus applied a probing approach to a tough fortified position, a flanking move and the use of his reserve, while the disaster at Atuatuca in 54 BC shows how differently a legate's decisions could end. The wider machinery of Roman command in the north is explored in our account of Rome's generals on the Rhine.

From Aquitania to Carrhae

Publius left Gaul around 54 BC, when his father went east. Plutarch reports that Caesar sent him with a force of Gallic cavalry and that he was part of the army that Marcus Crassus led into Mesopotamia (Plutarch, Crassus 17-25). When the Parthians drew the Roman army out into open ground at Carrhae, Plutarch has Publius pursue what looked like a retreating enemy with his cavalry, archers and infantry, only to be cut off and surrounded by Parthian cataphracts and horse archers. Wounded, he is said to have had his shield-bearer kill him, and his head was later shown to his father (Plutarch, Crassus 25-26). Plutarch's story is a literary construction and it is hard to say how much of it is accurate. But it makes a point: the aggressive tactical skill that won in Aquitania was not enough against a mounted enemy that Roman commanders had not faced before. Marcus Crassus, whose catastrophic expedition has its own account here, did not long survive his son.

Conclusion

Publius Crassus has one of the oddest records in Roman history. He was a competent subordinate who won two operations in two summers, and he is remembered for the third one he lost. The Aquitanian campaign gives a more useful picture of him: the legate who sensibly asked for a council, who recruited locally, and who took the risk of splitting his force at the right moment. It also demonstrates how thinly the English-language literature covers the less famous years of the Gallic War. His Aquitanian victory deserves to be read alongside the better-known Gallic sieges, as an example of what Rome's junior commanders could do when left alone.

Frequently asked questions

Who was Publius Crassus? Publius Licinius Crassus was the younger son of Marcus Crassus, the wealthy politician who formed the First Triumvirate with Caesar and Pompey. He served as one of Caesar's legates in Gaul from 58 BC, and he died at Carrhae in 53 BC.

Where was Aquitania in 56 BC? Caesar's Aquitania lay between the Garonne, the Pyrenees and the Atlantic, a smaller area than the later Roman province of the same name. Its tribes, including the Sotiates, Vocates and Tarusates, were in the region of modern Gascony.

Why did Spanish troops fight in Aquitania? The Aquitanian tribes sent for help across the Pyrenees, and according to Caesar they received troops from Hispania Citerior with officers who had served under Sertorius. Caesar's account is the only source, so the detail of this alliance cannot be checked.

Is Book III of the Gallic War reliable on this campaign? It is the only detailed narrative, but Caesar was not present and he wrote for a Roman audience. Numbers in particular, such as the 50,000 men said to have assembled, should be treated as claims rather than as measurements.

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