Vienne is a commune in Southeastern France, located 35 kilometres south of Lyon, at the confluence of the Gère and the Rhône. It is the fourth largest city in the Isère department, of which it is a subprefecture alongside La Tour-du-Pin, with a population of 29,583 as of 2018. However, in the past, Vienne was a major centre of the Roman Empire under the Latin name Vienna.
Before the arrival of the Roman armies, Vienne was the capital city of the Allobroges, a Gallic people. Transformed into a Roman colony in 47 BC under Julius Caesar, Vienne became a major urban centre, ideally located along the Rhône, then a major axis of communication. Emperor Augustus banished Herod the Great's son, the ethnarch Herod Archelaus to Vienne in 6 AD.
The town became a Roman provincial capital and remains of Roman constructions are everywhere in modern Vienne. The town was also an important early bishopric in Christian Gaul. Its most famous bishop was Avitus of Vienne. At the Council of Vienne, convened there in October 1311, Pope Clement V abolished the order of the Knights Templar.