The area was inhabited in the
Bronze Age. At the end of the 4th century BC, Vaison became the capital of a Celtic tribe, the
Vocontii, centred on the
oppidum in the upper city.
The Roman period After the Roman conquest (125–118 BC) in the wars against the
Salyes, the Vocontii retained a certain degree of autonomy; they had two capitals,
Luc-en-Diois, apparently the religious centre, and Vaison which was named
Vasio Julia Vocontiorum. Their authority continued in the gradual
Romanisation of the Celtic
oppidum. Early building was probably done by Vocontian aristocrats who moved down from the
oppidum and established houses along the river, around which the city eventually accreted but based on a Roman orthogonal street plan with different alignment from the earlier houses. Construction of large public monuments began in the second half of the 1st century: theatre, bridge, aqueducts, thermal baths. Two aqueducts provided water to the city; the older one had its source on the Sainte-Croix hill to the north, while the longer one's source was at the Groseau spring on Mont Ventoux to the south-east. The
Pax Romana led to the extension of the city which was at its finest in the 2nd century, when it covered up to . It became one of the richest of
Gallia Narbonensis; many houses with numerous mosaic pavements have been discovered and there is a fine theatre on a rocky hillslope, probably built during the reign of
Tiberius, whose statue was found in a prominent place on site. The statue, the
Vaison Diadumenos (now in the
British Museum), was also discovered in the theatre in the 19th century. The barbarian invasions were presaged by pillaging and burning in 276, from which Roman Vasio recovered. Vaison became a relatively important Christian religious centre (a bishopric existed there from the 4th century) where two councils met in 442 and 529.
The Post-Roman period The barbarian invasions of the 5th century by the
Burgundians ruined the city. The theatre's benches began to be reused as Christian tombstones. Vaison was taken by the
Ostrogoths in 527 then by
Chlothar I,
King of the Franks, in 545 and became part of
Provence. Disputes in the 12th century between the
counts of Provence, who had refortified the ancient "upper town", and the bishops, each of whom were in possession of half the town, were injurious to its prosperity; they were ended by a treaty negotiated in 1251 by the future pope
Clement IV, a native of
Saint-Gilles-du-Gard. In disturbed times of the Middle Ages, the inhabitants migrated to higher ground on the left bank of
Ouvèze, with the shelter of the ramparts and a strong castle. From the 18th century, most of the population moved back down to the plains by the river. A flood struck Vaison-la-Romaine on 22 September 1992, the worst since 1632. ==Population==