Vercassivellaunos was a Gallic aristocrat from the city of Arvernes, cousin of Vercingetorix. Its name is composed like that of its famous cousin:the intensive prefix ver- precedes a Gallic name attested elsewhere. The latter, Cassivellaunos, is itself composed of Vellaunos which means "the commander" and cassi which can refer to the term catu, "the battle"[1]. Vercassivellaunos would therefore be the "supreme commander of the battle".
He is one of the Gallic leaders during the insurrection of -52. It is mainly known to us through the story of the Gallic war by Julius Caesar. After the start of the siege of Alesia, he was chosen by the assembly of rebellious Gallic chiefs to lead the relief army with Commios the Atrebate and the Aedui Viridomaros and Eporedorix (César, BG, VII, 76, 3). They then find themselves, according to Caesar, at the head of 8,000 cavalry and 140,000 infantry gathered in Aedui territory. This relief army is intended to break the siege. During the attack, Vercassivellaunos is in command of a surprise offensive at the head of 60,000 men chosen from the cities with the most warlike reputation (BG, VII, 83). His attack is against the mountain, that is to say Mont Réa and threatens the cohesion of the Roman lines. Caesar responds by sending his legate Labienus and six cohorts to the site, then goes directly to the scene. The arrival of Caesar's cavalry routs the troops of Vercassivellaunos, who is captured alive by the Romans as he tries to flee (BG, VII, 88). The identification, thanks to the presence of sling balls marked "T(itus) LABI(enus)", of camp C of Alise with the camp of Labienus has recently made it possible to better understand this episode:installed on the mountain of Bussy , Labienus had a direct view of Mont Réa, including its reverse from which the Gauls emerged. He was both the closest legate and the least threatened.
The Arvernian coins of the VERCA legend have often been attributed to Vercassivellaunos, many of which have been found on the plateau of the oppidum of Gergovia, but they are sometimes considered to be later, and perhaps relate to one of his descendants.
The failure of Vercassivellaunos and the relief army precipitates the surrender of Alesia and her relative Vercingetorix. The definitive lowering of the Vercingetorix family subsequently led to the coming to power, among the Arverni, of Caesar's faithful like Epasnactos.