The territory of the Vocontii was east of the River Rhône, in the Prealps, between the rivers Drôme and Durance. Its northern limit was the valley of the Drôme. Its western limits were the first ridges of the Prealps, from the Forêt de Saou range in the north, the first ridges of the Baronnies Massif in the centre and, in the south, the Dentelles de Montmirail chain, just south of Vaison-la-Romaine, and Mont Ventoux which both form the western end the Monts de Vaucluse. In the south and the east, it was bounded by the Durance, expect for its uppermost tract in the Cottian Alps and its lowest tract in the plain by the Rhone. This area covered parts of the Drôme, Vaucluse and Alpes-de-Haute-Provence departments of modern France.
The area where the Vocontii lived is outlined in two passages by Strabo, who wrote in the first few decades of the 1st century CE:
- But if you go by the other road — that leads through the country of the Vocontii and that of Cottius Cottian Alps: from Nemausus Nîmes the road is identical with the former road as far as Ugernum (Beaucaire) and Tarusco (Tarascon), but thence it runs across the Druentia River [Durance] and through Caballio (Cavaillon) sixty-three miles to the frontiers of the Vocontii and the beginning of the ascent of the Alps; and thence, again, ninety-nine miles to the other frontiers of the Vocontii, at the country of Cottius, to the village of Ebrodunum (Embrun); then, another ninety-nine through the village of Brigantium Briançon and Scingomagus  and the pass that leads over the Alps (Col de Montgenèvre) to Ocelum (Oulx), the end of the land of Cottius. Moreover, from Scingomagus on you begin to call the country Italy; and the distance from here to Ocelum (Uxeau). is twenty-eight miles.
- After the Sallyes come the Albienses and the Albioeci and the Vocontii, who occupy the northerly parts of the mountains. But the Vocontii, stretching alongside the others, reach as far as the Allobroges; they have glens in the depths of their mountainous country that are of considerable size and not inferior to those the Allobroges have.
The Roman town of Noviomagus was probably Nyons. This town and Vasio (Vaison-la-Romaine) were not on the mountains. They were at the foot of the fist prealpine ridges, at the edge of the plain of the Rhône (the Dentelles de Montmirail were just to the south of Vasio; the Éssaillon, Garde-Grosse, Saint Jaumes and Vaux formed a half crescent by Noviomagus).
During the 4th century BCE, the Celtic Vocontii became settled there, with an oppidum south of modern Vaison (Garcia p. 168); this seems to have been used to control trade between the Rhône and Durance rivers (Meffre).
- After composing the dissensions of the Allobroges, when he now was proceeding to the Alps, he directed his course thither, not by the straight road, but turned to the left into the country of the Tricastini, thence by the extreme boundary of the territory of the Vocontii he proceeded to the Tricorii; his way not being anywhere obstructed until he came to the river Druentia. In 121 BC
The Vocontii were defeated by Marcus Fulvius Flaccus, a Roman consul, in 125 BCE and by Gaius Sextius Calvinus, a Roman proconsul, in 123 BCE during military campaigns against the Ligurians and Salluvii who lived to their south. In 121 BC Quintus Fabius Maximus Allobrogicus and Gnaeus Domitius Ahenobarbus defeated the Allobroges, who lived to the north of the Vocontii, and the Averni, who lived to the west of the River Rhône. In 118 BC Gnaeus Domitius founded a Roman colony at Narbo, near Hispania. Southern Gaul came under Roman control and was known as Gallia Transalpina. Over time it came to be organised as a province of the Roman Empire. With the reorganisation of the provinces of the Roman Empire under Augustus, Gallia Transalpina was renamed Gallia Narbonensis. It was named after Narbo, which became its capital.
Pliny the Elder, who wrote in the 70s AD, referred to the Vocontii as allies. This means that they were not turned into Roman subjects. They remained autonomous. They were allowed to continue to observe their own laws and did not have to pay a tribute. However, they had to supply auxiliary soldiers to Rome. The date of the grant of an alliance treaty (foedus) is unknown. Goudineau had speculated that it may have been made by Gaius Pomptinus after he suppressed the last rebellion of the Allobroges in 61 BCE when he was the governor of Gallia Transalpina  However, this is not certain. Pliny also named the town of Vasio in his record of people and places which had Latin rights.
When Marcus Fonteius, was governor of Gallia Transalpina, either in 76-74 or 74-72 BC, he was attacked by the Vocontii. He defeated them. Cicero did not say why they rebelled. Presumably this was connected to the heavy indebtedness with was incurred by the Gauls in the region which was due to taxes which were levied by Fonteius to raise money for the Roman troops which were fighting in the Sertorian War (80-72 BCE) in Hispania. Pompey, one of the commanders in that war, had crossed Gaul to go to Hispania and subdued some (unspecified) rebellious tribes there. Pompey used Gallia Transalpina, which was on the road to Hispania and, therefore, his line of communications, as a base for his operations in the Iberian Peninsula. He wintered in Gaul in 75/74 BCE. Fonteius also raised corn for the Roman troops and a Gallic cavalry to support them.
The Vocontii were mentioned by Julius Caesar (note that Further Province and Hither Province stand for Gallia Transalpina and Gallia Cisalpina; the latter was in northern Italy) :
- ... Here (in the Alps) the Ceutrones and the Graioceli and the Caturiges, having taken possession of the higher parts, attempt to obstruct the army in their march. After having routed these in several battles, he arrives in the territories of the Vocontii in the Further Province on the seventh day from Ocelum, which is the most remote town of the Hither Province; thence he leads his army into the country of the Allobroges,...
- The army then proceeded by slow marches through the territory of the Allobroges and Vocontii, the very length of each day's march and the changes of encampment being made a matter of traffic by the general, who concluded disgraceful bargains to the injury of the holders of land and the magistrates of the different states, and used such menaces, that at Lucus, a municipal town of the Vocontii, he was on the point of setting fire to the place, when a present of money soothed his rage.
The administrative reforms of Diocletian (reigned 284-305) abolished the old provinces and created new, smaller ones. The number of provinces was doubled. The Roman towns built on the site of or near Vocontian settlements close to the Rhône, Vasio and Noviomagus, and those on the River Drôme, Dia Augusta and Lucius Augustii, came under the Provincia Viennensis. Segusturo, and the area in the Alpes-de-Haute-Provence department came under the Provincia Narbonensis II
Rivet gives an account of the archaeological finds in Roman towns in Vocontian territory. These towns were:
- Dea Auguta (Die). At some point it took over control of the northern region from Lucus Augustii. It was a substantial settlement which owed its prosperity to its position on a main route from the Rhône to Italy. Its importance is shown by the fact that it had two aqueducts. One was seven km long and came from the northeast. The other was five km long and came from the southeast. It is not clear when it first became a bishopric. It is possible that Nicasius, who attended the Council of Nicaea in 325 came from Dea.
- Lucus Augustii (Luc-en-Diois). Only two inscriptions have been found, one dedicated to Mercury and the other to Dea Augusta Andarta, the dominant local deity.
- Noviomagus, which was most probably Nyons. Ptolemy attributed the town to the Tricastini. Archaeology has not yielded much, and the plan of the town is unknown. Mosaics, statues and funerary inscriptions have been found.
- Vasio (Vaison-la-Romaine). The pre-Roman settlement must have been an Oppidum. The Roman town was built on the other bank of the river. It was in Pomponius Mela's list of wealthy towns. It had a theatre capable of seating 7,000 people, several public baths and an aqueduct. It was laid out in the formal Roman way. The oldest traces of buildings, which were slightly improved in 20-30 BCE and reconstructed in fully Roman style in the Flavian period (69-96 BCE), go back to the 40-30 BCE.
- Segusturo (Sisteron). Excavations have not unearthed much. A second century funerary monument, a few fourth century graves and traces of some buildings have been found.
One finds a praetor and a senate leading the city of Vaison, assisted by praefecti sent to the surrounding districts (pagi), which were advised by local assemblies (vigintiviri). Public municipal officials and slaves supplemented this administrative system.
A 500-strong auxiliary cavalry unit, the Ala Augusta Vocontiorum civium Romanorum, was raised among the Vocontii. The troopers were Roman citizens. From 122, after service in Germania Inferior, it served at Trimontium, a mixed cavalry and infantry fort near Newstead, Scottish Borders. The unit is known by an inscription, (RIB 2121):
- Campestr(ibus) / sacrum Ael(ius) / Marcus / dec(urio) alae Aug(ustae) / Vocontio(rum) / v(otum) s(olvit) l(ibens) l(aetus) m(erito)
(To the sacred Goddesses of the Parade-Ground, Aelius Marcius, decurion¹ of the Vocontian Wing, willingly, gladly and deservedly fulfilled his vow.)
- Possibly the village of Chamblat de Seugin, which is just past the Montgenèvre pass, slightly off the Valley of Susa and at the foot of the Col des Sestrieres (Colle Sestriere), which leads to the Val Pragelas (Val Chiasone) as argued by D’ Anville
- A village in the valley of Susa, Italy; not to be confused with Uxeau in the Saône-et-Loire department
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