Bagacum: capital of the Nervii, a tribe in northern France/western Belgium. The city is now called Bavay.
The name "Bagacum" suggests that the first inhabitants spoke a Celtic language, but it is not entirely clear when these people settled over there. There are several Late Iron finds, but it is certainly possible that the Romans, after exterminating the Nervii (who suffered heavily in the battle at the river Sabis), repopulated the area. That would not be unique: Tongeren, Cologne, and Nijmegen are other examples of towns with no ethnic continuity from the Iron Age to the Early Roman Period.
The position of Bagacum as a node in the network of Roman roads suggests that it was, on its present location, founded by Agrippa, who created this network in 39/38 or 20-18 BCE. From Bavay, there were straight roads to
- the east-northeast to Tongeren and Cologne (the so-called "Chaussée Brunehaut"),
- to the east to Dinant,
- to the east-southeast to Trier,
- to the southeast to Reims,
- to Cambrai and Vermand in the southwest,
- to Arras in the west,
- to Blicquy in the northnorthwest,
- and to Tournai in the north.
Many of these ancient roads are still in use and are called "Chaussée Brunehaut", after the Frankish queen Brunhilda who - according to a fouteenth-century legend - repaired the roads.
As administrative capital of the Nervii, Bavay expanded quite rapidly. The Roman government invested much money in the city. The basilica on the forum, for example, was one of the largest of the Roman world, and it would seem that the people were loyal to the government: Nervian soldiers are mentioned as supporting the pro-Roman leader Claudius Labeo during the Batavian Revolt.
The city continued to flourish. In the second century, the city had expanded to some 45 hectares. However, this attracted enemies. In 172 CE, the Chauki launched a devastating campaign against western Belgica, where the capital cities of the Morini and the Nervi, Thérouanne and Bavay, were so extensively damaged that they had to be rebuilt completely.
Nevertheless, the city was rebuilt. It was less lucky after the defeat of the Gallic Empire. The new ruler, Aurelian, massacred many troops and transferred the remainder, allowing the Franks to sack the northern cities. Cologne was plundered, Maastricht put to the torch, Tongeren gutted, Bavay levelled to the ground.
Cambrai was to be the new capital of this part of Belgica. In Bavay, only the forum area, some four hectares, remained inhabited.