Vienne is a town in southeastern France, located 35 kilometres south of Lyon, at the confluence of the Gère and the Rhône. It is the fourth-largest commune in the Isère department, of which it is a subprefecture alongside La Tour-du-Pin. Vienne was a major centre of the Roman Empire under the Latin name Vienna. Vienne was the capital of the Allobroges, a Gallic people, before its conquest by the Romans.