a Trevir, was prefect of an ala of the Treviri in the Roman army on the Rhine, under Vitellius, A. D. 69 (Tac. Hist. 2.14), and afterwards joined Civilis at the head of some of the Treviri in his rebellion against the Romans, A. D. 70. During the first part of the war with Civilis, the Treviri, like the rest of Gaul, remained firm to the Romans. They even fortified their borders, and opposed the Germans in great battles. (Tac. Hist. 4.37.) But when the news of Vitellius's death reached Gaul (A. D. 70), there arose a rumour that the chiefs of Gaul had secretly taken an oath to avail themselves of the civil discords of Rome for the recovery of their independence. There was, however, no open sign of rebellion till after the death of HORDEONIUS FLACCUS, when messengers began to pass between Civilis and Classicus, who was still commanding an ala of Trcvirans in the army of Vocula. He was descended from a family of royal blood and of renown both in peace and war, and through his ancestors he accounted himself rather an enemy than an ally of the Roman people. His conspiracy was shared by JULIUS TUTOR, a Treviran, and JULIUS SABINUS, a Lingon. They met, with some Trevirans and a few Ubii and Tungri, in a house at Colonia Agrippinensis; and, having resolved to occupy the passes of the Alps, to seduce the Roman legions, and to kill the legates, they sent emissaries to rouse the Gauls. Vocula was warned of the plot, but did not feel strong enough to crush it. He even suffered himself to be enticed by the conspirators to leave his camp at Colonia and to march against Civilis, who was besieging Vetera Castra. The army was not far from this place, when Classicus and Tutor, having communicated privately with the Germans, drew off their forces and formed a separate camp. Vocula, after attempting in vain to gain them back, retired to Novesium. They followed at a little distance, and at length persuaded the disaffected soldiers of Vocula to mutiny against him; and in the midst of the mutiny Classicus sent into the camp a deserter named Aemilius Longus, who murdered Vocula. Classicus then entered the camp, bearing the insignia of a Roman emperor, and compelled the soldiers to take the oath to the empire of Gaul (pro imperio Galliarum). The command was now divided between Classicus and Tutor; and Classicus sent the worst disposed of the captured Roman soldiers to induce the legions who were besieged in Vetera Castra to surrender and to take the same oath. The further progress of the war is related under CIVILIS. The last mention of Classicus is when he crossed the Rhine with Civilis after his defeat by Cerealis, and aided him in his last effort in the island of the Batavi. (Tac. Hist. 4.54_79, 5.19_22.)