The Roman proconsul Domitius Ahenobarbus undertakes a war in 121 BCE against the Allobroges, who have allied with the Arverni under Bituitus.
These Gallic tribes are defeated near the town of Vindalium, the current French town of Bédarrides.
After this defeat, the Allobroges and Arverni make preparations to renter battle with the Romans.
Bituitus again takes the field with an large army.
Where the Isar meets the river Rhone in the south of France, the consul Fabius Maximus, the grandson of Paullus, meets them in battle in the autumn of 121 BCE.
The Romans are greatly outnumbered yet manage to gain a complete victory.
It is estimated that 120,000 of Bituitus' army fell in the battle.
Following his defeat, Bituitus is taken prisoner and sent to Rome.
The Arverni had once been the most powerful tribal hegemony in Gaul during the third and second centuries BCE under their king, Luernios, but with the defeat of his son (or grandson) Bituitus, their ascendancy passes to the Aedui and Sequani.
Unlike the Allobroges, who have been brought under direct Roman rule as a result of the Celtic wars of the 120s, the Arverni negotiate a treaty that preserves their independence, though their territory is diminished.
No further Arvernian kings are mentioned in the historical record, and they may have adopted a constitutional oligarchy at this time.
