Narbonensisin full Gallia Narbonensis, English Narbonese Gaulancient Roman province that lay between the Alps, the Mediterranean Sea, and the Cévennes Mountains. It comprised what is now southeastern France.

The area first entered ancient history when the Greek colony of Massilia (modern Marseille) was founded about 600 bc. Roman armies first entered the area in 154 bc to help defend Massilia against Celtic invaders. The Romans conquered southeastern Gaul in the years following 125 bc, In 121 bc the coast from what is now Montpellier to the Pyrenees—with its port of Narbo Martius (modern Narbonne) and its trade route by Tolosa (Toulouse) to the Atlantic—was annexed by Rome, and in 118 the city of Narbo itself was formed into a Roman colony and made the province’s capital. Roman traders and veterans then speedily flocked in to settle the area. Gradually the province was extended north of Massilia, up the Rhône. Originally named Provincia (“Province”), the province southern France is still known as Provence. During the reign of Augustus, Provincia was renamed Gallia Narbonensis during the reign of Augustusafter its capital, Narbo, to distinguish it from the three provinces of northern Gaul conquered by Julius Caesar in the 50s bc. The province became fully Romanized and was governed by a proconsul appointed by the Senate.

Narbonensis, the sun-steeped home of the vine and the olive, was in climate and history markedly different from the rest of Gaul; and it attracted a large number of Roman immigrants. Splendid buildings were erected, many of which have left impressive remains. To the prosperous vineyards and olive groves were added other industries, particularly in timber and specialized metalwork. Narbonensis was the birthplace of several men prominent in Roman public life. Agricola came from Forum Iulii (modern Fréjus); and it has been conjectured that his son-in-law, the historian Tacitus, was also Narbonese. The high level of culture in the province was famous, particularly the schooling provided at Massilia. Narbonese Gaul developed a prosperous urban culture, like that of Italy during the early centuries of the Roman Empire. Barbarian invasions and civil strife ended the prosperity during the 3rd century ad. The writings of the poets Ausonius (4th century) and Sidonius Apollinaris (5th century) reveal the resilience of Roman culture in southern Gaul until its conquest by the Franks under Clovis I in the late 5th century.