Pre-Roman period Origin The Allobroges probably settled relatively late in Southern Gaul, for they are not attested before the late 3rd century BC, in connection with
Hannibal's crossing of the Alps in 218 BC. According to some scholars, they may be identified with the
Gaesatae, a group of mercenary warriors first mentioned a few years earlier in the region and who fought against the
Roman Republic in the
Battle of Telamon (225 BC). The Allobroges may thus be the descendants of mobile groups of Gallic mercenaries who were active across central Europe in the first part of the 3rd century BC, and who eventually settled between the Rhône and the Alps in search for new opportunities during the later decades of the century.
Hannibal's crossing of the Alps (218 BC) In the mid-2nd century BC, the Greek historian
Polybius first mentioned the Allobroges in his account of
Hannibal's crossing of the Alps in 218 BC. The Allobroges of the plain helped the Carthaginian conqueror, whereas those of the mountains tried in vain to block his passage. Hannibal then expelled the other chieftain and was given new weapons, corn, warm clothing and footwear by his local ally. The latter protected him in the rear with his own forces through the territory of the Allobroges, until he reached the foot of the Alpine pass. In
Livy's version, the Gallic chieftain who provided assistance to Hannibal is named Brancus ('the claw', var.
Braneus). In 63 BC, while Cicero was serving as consul, they sent another delegation to Rome, hoping to seek relief from the oppression and rapacity of governor
Lucius Murena and Roman businessmen active in the region. Their demands rejected by the Roman Senate, they were approached by supporters of
Catiline, a senator who attempted to overthrow the
Roman Republic and, in particular, the power of the
aristocratic Senate. Seeing an opportunity to enlist their help to the
Catiline conspiracy,
Lentulus sent the businessman
Umbrenus persuade the Gallic envoys to invade Italy in support of Catiline. Although initially favourable to this overture, the Allobroges thought their fate would be better if they take the Senate's side. They contacted their patron
Q. Fabius Sanga, and Cicero convinced them to provide him with more evidence by feigning to join the conspirators. The supporters of Catiline then revealed their plan to the Gauls, who demanded sealed letters from some leading conspirators, which the Allobroges eventually leaked to Cicero.
Revolt against Rome (62–61 BC) Faced with a series of legal defeats, the Allobroges decided to take up arms against Rome in 62 BC. Led by their chief
Catugnatus, they managed to resist Roman armies for nearly two years. The new provincial governor,
Gaius Pomptinus, sent his
legate Manlius Lentinus to crush the revolt. from the 1st century BC.In 61 BC, a battle was fought between the Gallic and Roman troops near the
Segovellaunian settlement of Ventia, which was eventually taken by Lentinus. At the same time, the two other legates seized and partly destroyed the chief Allobrogian town, Solonion. The coming of Catugnatus' forces momentary saved the stronghold, but further Roman troops led by Pomptinus surrounded and defeated the Gallic armies, putting an end to the rebellion. Their capital destroyed, the Allobrogian chieftains decided to move their place of residence to
Vienna.
Political turmoils (58–44 BC) The period saw the invasion of the remainder of Gaul by
Julius Caesar, followed by a
civil war and
Caesar's assassination in March 44. Although the Helvetii thought they could persuade the Allobroges to let them go through their territory in 58 BC because of their antipathy to Rome, the Gallic tribe, presumably led at that time by Adbucillus, remained loyal to Caesar during all the
Gallic Wars (58–50 BC). The Roman general used Vienna in particular as a strategic outpost during the conflict against the Gauls. After the failed
migration of the Helvetii, who were repelled by the Romans towards their homeland, the Allobroges were asked by Caesar to provide them with wheat. In the autumn of 57, the legate
Galba spent winter in the Allobrogian territory after an unsuccessful campaign in Vallis Poenina (modern
Valais). Following the Roman defeat at the
Battle of Gergovia (52 BC), the Allobroges began to strengthen the border along the Rhône river, possibly fearing attacks coming from the other bank.
Vercingetorix tried to bribe their leaders to fight on the side of the Gallic coalition against Caesar, but the Allobroges rejected the offer. Two sons of Adbucillus,
Aegus and Roscillus, provided assistance to Caesar in all of his Gallic campaigns. He assigned to them the highest magistracies among their own people, and granted them both money and conquered territory in Gaul. Regrettably, Caesar records that these privileges caused the two brothers to become "carried away by a foolish native pride" and to "treat their men with contempt, cheating the cavalry of its pay and diverting all of the booty to themselves". Their own armies came to Caesar to complain, and the two brothers eventually defected to
Pompey at
Dyrrachium just before the
Battle of Pharsalia (48 BC).
Roman Empire Strabo reported in the early 1st century AD that all the Allobroges lived in villages, "except that the most notable of them, inhabitants of Vienna (formerly a village, but called, nevertheless, the 'metropolis' of the tribe), have built it up into a city." At the time of the late Roman Empire, the Allobrogian territory was divided and administered from the three main cities: Vienna, Geneva and Cularo (later renamed Gratianopolis). ==Religion==