After the Battle of Axona, Caesar continued his advance and tribes surrendered one by one. However, four tribes, the Nervii, the Atrebates, the Aduatuci, and the Viromandui refused to submit. The Ambiani told Caesar that the Nervii were the most hostile of the Belgae to Roman rule. A fierce and brave tribe, they did not allow the import of luxury items as they believed these had a corrupting effect and probably feared Roman influence. They had no intention of entering peace negotiations with the Romans. Caesar would move on them next.

The Battle of the Sabis was fought in 57 BCE near modern Saulzoir in Northern France, between Caesar's legions and an association of Belgae tribes, principally the Nervii. Julius Caesar, commanding the Roman forces, was surprised and nearly defeated. According to Caesar's report, a combination of determined defence, skilled generalship, and the timely arrival of reinforcements allowed the Romans to turn a strategic defeat into a tactical victory. Few primary sources describe the battle in detail, with most information coming from Caesar's own report on the battle from his book, Commentarii de Bello Gallico. Little is therefore known about the Nervii perspective on the battle. The Veneti, the Unelli, the Osismii, the Curiosolitae, the Sesuvii, the Aulerci and the Rhedones were all brought under Roman control following the battle.