Narbo (modern Narbonne) had been established in Gaul in 118 BCE, as Colonia Narbo Martius.

Located on the Via Domitia, the first Roman road in Gaul, built at the time of the foundation of the colony, and connecting Italy to Spain, Narbonne is therefore located at a very important crossroads because it is situated where the Via Domitia connects to the Via Aquitania, which leads toward the Atlantic across Toulouse and Bordeaux.

In addition, it is crossed by the Aude River.

Politically, Narbonne has gained importance as a competitor to Marseille.

Julius Caesar settles veterans from his Tenth Legion there (while those of the Thirteenth are given somewhat better lands in Italia itself) and attempts to develop its port while Marseille was revolting against Roman control.

Later, the provincia of southern Gaul would be named "Gallia Narbonensis", after the city, and Narbonne would become its capital.

Seat of a powerful administration, the city will enjoy economic and architectural expansion and become a prosperous port (though it is today located about fifteen kilometers from the shores of the Mediterranean Sea).