In Italy, the new year 70 started with excellent omens. The civil war was over, Vitellius was dead, the new emperor Vespasian turned out to be a kind man, and plans were made to put an end to the Jewish war and the Batavian revolt. The big question was whether the expeditionary force sent across the Alps was in time to prevent the situation north of Mainz from escalating. As it turned out, the Roman reinforcements arrived too late. The murder of Marcus Hordeonius Flaccus by his own men, just after he had restored order at Bonn, Cologne, Neuss, and Vetera, had given the defeated rebels new self-confidence. Julius Civilis had renewed the siege of the Fifth legion Alaudae and Fifteenth legion Primigenia at Vetera, and the Trevirans and Lingones, ancient Gallic but romanized tribes living along the Mosel and upper Rhine, decided to revolt, too.
They had seen that the three legions that had temporarily lifted the siege of Vetera (First legion Germanica, Sixteenth legion Gallica, Twenty-second legion Primigenia) were too small to deal effectively with the situation. Of course, the Batavian defeats at Krefeld, Vetera, and Neuss had done something to restore Roman prestige, but the knowledge that Julius Civilis was again besieging Vetera and the obvious division among the Roman legionaries took away the last doubts among the Trevirans and Lingones.
The last Roman success was the relief of Mainz (which was now garrisoned with the Fourth legion Macedonica and the Twenty-second), but when general Caius Dillius Vocula set out to offer help to the garrison at Vetera, his Treviran and Lingonian auxiliaries deserted. Tacitus introduces the protagonists as follows.
Messages were exchanged between Civilis and Julius Classicus, the commander of the Treviran cavalry regiment. The latter's rank and wealth put him in a class above others. He was descended from a line of kings, and his forebears had been prominent in peace and war. Classicus himself was in the habit of boasting that he counted among his ancestors more enemies of Rome than allies. Also involved were Julius Tutor and Julius Sabinus, the former a Treviran, the latter a Lingon. Tutor had been placed by Vitellius in command of the west bank of the Rhine. Sabinus for his part, naturally a conceited man, was further inflamed by bogus pretensions to high birth. He claimed that the beauty of his great-grandmother had attracted Julius Caesar during the Gallic War and she had become his mistress.
The rebellion of Julius Classicus, Julius Tutor and Julius Sabinus has to be distinguished from the revolt of the Batavians. As we will see, the Trevirans and Lingones were fully romanized and wanted to start an empire of their own -the Gallic empire- whereas the Batavians wanted independence of some sort (their war aims are discussed above).
When Vocula saw that Classicus and Tutor persisted in their treachery, he turned round and retired to Neuss. The Gauls encamped three kilometers away on the flat ground. Centurions and soldiers passed to and fro between the camps, selling their souls to the enemy. The upshot was a deed of shame quite without parallel: a Roman army was to swear allegiance to the foreigner, sealing the monstrous bargain with a pledge to murder or imprison its commanders.
The former adherents of Vitellius must have found it easy to break their oath to Vespasian. Vocula was killed by a soldier of the First legion Germanica, and Julius Classicus, dressed in the uniform of a Roman general, appeared at the camp and read out the terms of the oath: the legionaries of the First and Sixteenth legions had to uphold the Gallic empire and support its emperor, Julius Sabinus (the fifth emperor in the Roman world in thirteen months). Thereafter, Tutor attacked troops in Cologne and Mainz, and Classicus sent some of the troops who had capitulated to Vetera to offer quarter to its garrison and lure them into surrender. However, the commander of the beleaguered soldiers, Munius Lupercus, refused to come to terms.
After this, the First and Sixteenth were directed to Trier, far away from the theater of war. Their new emperor Sabinus did not fully trust them. Perhaps he should have used them, because his war against the Sequani (who lived along the Sa˘ne) was unsuccessful.
Sabinus' rashness in forcing an encounter was equaled by the panic which made him abandon it. In order to spread a rumor that he was dead, he set fire to the farmhouse where he had taken refuge, and people thought that he had committed suicide there.
With the Sequanian victory, the war movement in Gaul came to a halt. Gradually the communities began to recover their senses and honor their obligations and treaties. In this the inhabitants of Reims took the lead by issuing invitations to a conference which should decide whether they wanted independence or peace.
The result was that the Gauls invited the Trevirans and Lingones to stop their aggression, especially now that the Gallic emperor was (or seemed) dead. However, they refused to do so, and sided with Julius Civilis.