The first Roman target was Trier, which commanded an important road from the Mediterranean to the Rhine. Three armies were threatening the capital of the Trevirans: the two legions that had returned to the Roman side; the Sixth legion Victrix and the First Adiutrix from Spain; and Cerialis' XXI Rapax from the east. Since Julius Civilis was still chasing the guerilla warriors of Claudius Labeo, the Trevirans had to bear the brunt of the battle all alone. They tried to obstruct the latter's advance near a town called Rigodulum (probably modern Riol), but were defeated. Next day, Cerialis entered Trier. Here, he encountered the legionaries of I Germanica and XVI Gallica. Cerialis was kind towards them, and showed clemency towards the Trevirans and Lingones, punishing only those who were really guilty of treason.
From this moment on, the Romans were not only superior in tactics, discipline, and experience, but also in numbers. However, their armies had not united yet, and this offered an opportunity to Julius Civilis and his allies Julius Tutor and Julius Classicus. They decided to destroy the army at Trier during a nightly surprise attack. It may have been the moonless night of June 7/8, but this is far from certain. The Romans were indeed surprised and their enemies were able to penetrate the camp, but ultimately the three legions were able to expel the rebels. In fact, this was the decisive battle of the war: from now on, Cerialis could start to reconstruct the Rhine border -the four legions at Mainz may already have made a start- and mop up the last resistance.