 Cicero did not say why they rebelled.Presumably this was connected to the heavy indebtedness with was incurred by the Gauls in the region which was due to taxes which were levied by Fonteius to raise money for the Roman troops which were fighting in the Sertorian War (80-72 BCE) in Hispania.Pompey, one of the commanders in that war, had crossed Gaul to go to Hispania and subdued some (unspecified) rebellious tribes there.