|Hannibal vs. Allobroges|
The first reference to the Allobroge tribe of Gaul is made by the Greek historian, Polybius, who described Hannibal's crossing of the Alps in 218 BC. They were one of the richest and most powerful nations of Gaul. Because of their territory, among the most extensive in south-eastern Gaul, they controlled part of the Rhône Valley, and were situated at the point where all the roads across the Alps arrived.
The Allobroges attempted to prevent Hannibal from crossing when he entered the first passes. But they were not successful.
The Allobroges were an important Gaulish tribe, situated in the south eastern part of France roughly corresponding to the modern French département of Isère; east of the Massif Central and west of the Alps, in the valley of the river Rhône, where it is joined by the river Saône. Their territory also extended to the north-east towards the south of modern Switzerland, (Savoie and Haute-Savoie) and thus they guarded the many alpine passes that lead to modern Italy.
Vienne was the capital of the civitas of the Allobroges. It was a port on the major trade route of the Rhône river, and the foundations of extensive river-side warehouses have been discovered. The nearest major towns are Lyon, Saint-Etienne and Grenoble.Their sphere of influence seems to have extended over about the same territorial area as that of the city-state of Vienne under the Romans.
Surrounding tribes were the Ambares, to the north, and the Aedui to the north of them; the Sequani and the Helvetii to the north-east; to the south east, right on the Alps, were the Ceutrons and the Vocontii (who might not be Celtic, but Ligurian). To the south were the Segovellauni; further south and south-west were smaller tribes, the Cavares, Helveni and Velaves; and far to the west across the Massif Central were the Arverni.
The Allobroges, who were first of all warriors, possessed vast arable lands (their wheat was famous in Roman times). Perhaps they already had vineyards. Like all alpine populations, they practised animal husbandry, forestry and probably mining. Since they controlled several "international" trading route axes, they certainly derived substantial revenues from tolls on road traffic passing up the Via Agrippa, the major Roman road that connected Arelete (modern Arles) near the Mediterranean coast with Lugdunum (modern Lyon), the capital of Gallia Comata. Several roads from Rome, coming through Alpine passes, also connected to Vienne.
Although the initial oppidum of the Allobroges was described by Strabo as little more than a village, wealth from trade and agriculture (wheat and wine) rapidly increased this; Tacitus in his Annals calls Vienne in 100 ad a "historic and imposing city". For example, they had the second-largest theatre in Gaul (the largest was at Autun).
Polybius describes the struggle with Hannibal (History, III, 50 translated by G. Barruol):
"Hannibal had been going up the river [the Isère] for ten days, he had covered 800 stadia [148 km] and was climbing the lower slopes of the Alps when he found himself exposed to a very serious threat. As long as he had been on flat ground [the valley of the middle and lower Isère in Allobroge territory], none of the Allobroge chiefs had dared attack the Carthaginians, either for fear of the [Carthaginian] cavalry or of the Barbarians escorting them [the Segovellauni, neighbours of the Allobroges, who lived between the junctions of the Drôme and the Isère with the Rhône]. But when the Segovellauni had returned to their land of origin and Hannibal began to enter the mountain range, the Allobroge chiefs, acting in concert, gathered a considerable contingent and occupied the positions that dominated the places where he would necessarily have to go through [the Arc valley, territory belonging to the Ceutrons, neighbours of the Allobroges]".
The Allobroge Gauls | Gaul Before the Romans
Musée Archéologique De Viuz Faverges (in French or English; the French site has more info.)
Sites and Museums in Roman Gaul: Vienne and St. Romain-en-Gal
Virtual Vienne website (in English or French; excellent site)