How did Brancus help Hannibal’s army during its march through Gaul?

During his march through Gaul, Hannibal encountered a civil war between two brothers, both of whom were likely Allobroges chieftains, in a fertile region known as "the island." Brancus, the elder brother, sought Hannibal’s assistance in this conflict. In exchange for Hannibal’s military support, Brancus provided essential supplies to the Carthaginian army, which was in dire need of provisions after having marched approximately 750 miles from Cartagena.1

This intervention, however, may have angered other members of the Allobroges tribe, who subsequently ambushed the rear of Hannibal’s column as he began his crossing of the Alps.2