The approach of Cerealis, the Roman general sent by Vespasian with a powerful army in the year 70, put an end to the Gallic insurrection. Most of the Gallic tribes submitted without resistance: the Treviri, on the Moselle, were defeated in battle, the cities and fortresses on the western bank of the Rhine were retaken, and the Roman frontier was re-established. Nevertheless, the German tribes which had been allied with the Gauls--among them the Batavi--refused to submit, and they were strong enough to fight two bloody battles, in which Cerealis was only saved from defeat by what the Romans considered to be the direct interposition of the gods. The Batavi, although finally subdued in their home in Holland, succeeded in getting possession of the Roman admiral's vessel, by a night attack on his fleet on the Rhine. This trophy they sent by way of the river Lippe, an eastern branch of the Rhine, as a present to the great prophetess, Velleda. The defeat of the German tribes by Cerealis was not followed by a new Roman invasion of their territory. The Rhine remained the boundary, although the Romans crossed the river at various points and built fortresses upon the eastern bank. They appear, in like manner, to have crossed the Danube, and they also gradually acquired possession of the south-western corner of Germany, lying between the head-waters of that river and the Rhine. This region (now occupied by Baden and part of Würtemberg) had been deserted by the Marcomanni when they marched to Bohemia, and it does not appear that any other German tribe attempted to take permanent possession of it. Its first occupants, the Helvetians, were now settled in Switzerland. [Sidenote: 100.] The enlisting of Germans to serve as soldiers in the Roman army, begun by Julius Cæsar, was continued by the Emperors. The proofs of their heroism, which the Germans had given in resisting Germanicus, made them desirable as troops; and, since they were accustomed to fight with their neighbors at home, they had no scruples in fighting them under the banner of Rome. Thus one German legion after another was formed, taken to Rome, Spain, Greece or the East, and its veterans, if they returned home when disabled by age or wounds, carried with them stories of the civilized world, of cities, palaces and temples, of agriculture and the arts, of a civil and political system far wiser and stronger than their own.