The Nervii were one of the most powerful Belgic tribes of northern Gaul at the time of its conquest by Rome. Their territory corresponds to the central part of modern Belgium, including Brussels, and stretched southwards into French Hainault. During their 1st century BC Roman military campaign, Julius Caesar's contacts among the Remi stated that the Nervii were the most warlike of the Belgae. In times of war, they were known to trek long distances to take part in battles. Being one of the distant northern Belgic tribes, with the Menapii to the west, and the Eburones to their east, they were considered by Caesar to be relatively uncorrupted by civilization.
The territory of the Nervii had its western and northwestern border on the Scheldt (French Escaut) river and stretched in the south through Hainaut to the forests of Arrouaise and Thiérache. To the east, the boundaries are unclear but it is possible that they stretched as far as the Dyle river valley in the north, near Louvain, and the Meuse in the south in modern Wallonia, near Namur. An oppidum found near Asse may have belonged to them but it was isolated and near to the territory of the Menapii. A large population occupied the southern territories, near the river Sambre with the biggest being at Avesnelles, near Avesnes-sur-Helpe. Caesar also mentions smaller tribes who were expected to contribute troops to Nervian forces; Levaci, Pleumoxii, Geidumni, Ceutrones, and Grudii.
In the Middle Ages, Hainaut was sometimes referred to as the county of the Nervians (comitatus nerviensis) in medieval Latin, and when this came to be politically united with mainly Dutch speaking Brabant again, the counties were still distinguished in the official Latin titles (comitatus Nerviensis atque Bracbatensis). Today, Hainaut is divided between France and Belgium. To its north, parts of the modern Belgian provinces of Antwerp, East Flanders, Flemish Brabant and French-speaking Walloon Brabant approximate the rest of the old Nervian territory.
Although it is often assumed that the Nervii spoke a Celtic language, the evidence regarding their linguistic affiliation is inconclusive. The same applies to other Belgian tribes, like the Menapii and Morini, to the west of the Nervii on the English channel, and the Germani cisrhenani to the east of the Nervii, stretching to the Rhine.
Caesar writes that the Belgae generally had received immigration from Germanic people from east of the Rhine. The Romanized Greek Strabo wrote that the Nervii were of Germanic origin. Tacitus, in his book Germania, says that in his time the Nervii and Treveri both claimed Germanic ancestry, similar to that of their mutual neighbours the Tungri, in order to distinguish them from the weaknesses of the Gauls.
The Romans were not precise in their ethnography of northern barbarians: by "Germanic" Caesar may simply have meant "originating east of the Rhine" with no distinction of language intended. During Caesar's lifetime, Germanic languages east of the Rhine may have been no closer than the river Elbe. It has instead been argued based on place name studies that the older language of the area, though apparently Indo-European, was also not Celtic (see Nordwestblock) and that Celtic, though influential amongst the elite, might never have been the main language of the part of the Belgic area north of the Ardennes. On the other hand, these same studies of placenames such as those of Maurits Gysseling, have also shown evidence of Germanic languages entering the Belgic area north of the Ardennes, before the Roman conquest, while strong evidence for old Celtic place names is found in the Ardennes and to the south of them. Luc van Durme summarizes competing evidence of Celtic and Germanic influence at the time of Caesar by saying that "one has to accept the rather remarkable conclusion that Caesar must have witnessed a situation opposing Celtic and Germanic in Belgium, in a territory slightly more to the south than the early medieval Romance–Germanic language border", but van Durme also accepts that "second century BC Germanisation did not block the celtisation coming from the south . . . but that both phenomena were simultaneous and interfering instead".
Julius Caesar considered the Nervii to be the most warlike of the Belgic tribes, and that the Belgic tribes were the bravest in Gaul. He says that their culture was a Spartan one: they would not partake of alcoholic beverages or any other such luxury, feeling that the mind must remain clear to be brave. He also says they disliked foreign trade and had no merchant class / would not permit merchants within their territory.
Remarkably, given the archaeological evidence of a Celtic La Tène culture having been present in the pre-Roman past, Caesar reports that the Nervii had no cavalry. In fact they established hedges throughout their lands in order to make them difficult for cavalry.
The Frasnes hoard, accidentally unearthed by foresters in 1864 near Frasnes-lez-Buissenal in Hainaut, along with coins associated with the Morini and the Nervii, also contained characteristically Gallic gold torques, one of which was in Alastair Bradley Martin's Guennol collection.
The Nervii were part of the Belgic alliance that resisted Julius Caesar in 57 BC. After the alliance broke up and some tribes surrendered, the Nervii, under the command of Boduognatus and aided by the Atrebates and Viromandui, came very close to defeating Caesar (the Atuatuci had also agreed to join them but did not arrive in time). In 57 BC at the battle of the Sabis (now identified as the river Selle, near modern Saulzoir; previously identified as the Sambre), they concealed themselves in the forests and attacked the approaching Roman column at the river. Their attack was so quick and unexpected that some of the Romans didn't have time to take the covers off their shields or even put on their helmets. The element of surprise briefly left the Romans exposed. However Caesar grabbed a shield, made his way to the front line, and quickly organised his forces; at the same time, the commander of the tenth legion, Titus Labienus, attacked the Nervian camp. The two legions who had been guarding the baggage train at the rear arrived and helped to turn the tide of the battle. Caesar says the Nervii were almost annihilated in the battle and is effusive in his tribute to their bravery, calling them "heroes".
When Ambiorix and the Eburones rebelled in 53 BC, the remaining Nervii joined the uprising and besieged Quintus Tullius Cicero – brother of the orator – and his legion in their winter camp until they were relieved by Caesar in person.
The Nervian civitas was at Bagacum. The city was founded to the south of the traditional Nervian territory and is now known as Bavay, a town in France near the Belgian border. The forum has been excavated. The town was founded in c.30 BC and rapidly became a centre of Roman civilization. Towns belonging to the Nervian territory were Fanum Martis (Famars), and Geminiacum (Liberchies).
Inscriptions found on artifacts recovered at Rough Castle Fort along the Antonine Wall across the Central Belt of Scotland indicate that in the 2nd century the fort was the base for 500 men of the Sixth Cohort of Nervii, an infantry unit. According to Tacitus, the Nervians also served in cohorts based along the Rhine border. Altars found at the Roman fort of Whitley Castle in Northumberland, also known as Epiacum, bear inscriptions showing that the Second Nervians were garrisoned at the fort.
After the disastrous attacks by the Franks in 260-275 AD, a new chief city was designated at Camaracum (Cambrai), further south than Bavay, and Bavay itself, and the main road it was on, became part of a new secondary fortified border zone. The northern part of Nervian territory, which included the so-called Silva Carbonaria (Coal forest), became lightly populated, and eventually settled by Germanic groups, leaving the southern part, medieval Hainaut, more Romanized. By 432 it seems the country of the Romanized Nervians south and west of the forest and had been taken over by the Franks. Their king Childeric I was buried in Tournai. The medieval Roman Catholic Archdiocese of Cambrai continued to cover the same approximate area as the Roman civitas until 1559.
The Nervii and their western neighbours the Menapii are the main subjects of the comic book Asterix in Belgium. In it, a competition between the Belgians and the Gauls from Armorica takes place to decide who was the bravest, under the unlikely adjudication of Julius Caesar.
The Nervii are featured in the video game Total War: Rome II.