The Nervii were one of the most powerful Belgic tribes, living east of the Scheldt in northern Gaul in the 1st century BC; Caesar's informants among the Remi asserted that the Nervii were the most distant of Belgii. The Romanized Greek Strabo, however, wrote that the Nervii were of Germanic origin. Tacitus confirmed this in his book "Germania" (par. 28 and 29) adding: "they say that this noble blood separates them completely from the Gauls, and from the Gaul laziness". Based on a few literary sources, few of which were first-hand accounts, nineteenth-century ethnographers and their intellectual heirs have attempted ethnographic mapping of the region now covered by northernmost France and Belgium. The scant late La Tène material culture of the region does not throw light on linguistic affiliations, but metalwork from Bavay, the chief town of the Nervi, in the immediately following Roman period, where it is not imported or directly Roman in inspiration, is Gaulish.
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 had not yet arrived). At the battle of the Sabis (the modern river Selle), in 57 BC, 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 Nervians were well-known for the export of grain; an interesting tombstone of a frumentarius was excavated as far away as Nijmegen. They also produced ceramics (terra nigra).
Inscriptions found on artifacts recovered at Rough Castle Fort along the Antonine Wall across the central belt of Scotland indicate that in the second 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.
After the disastrous attacks by the Franks in 275, a new civitas was built at Camaracum (Cambrai). In 432 the country of the Nervians was officially taken over by the Franks. Their king Childeric I was buried in Tournai.