The German chief now agreed to an interview, and the two leaders met, half-way between the two armies, on the plain of the Rhine. The place is supposed to have been a little to the northward of Basel. Neither Cæsar nor Ariovistus would yield to the demands of the other, and as the cavalry of their armies began skirmishing, the interview was broken off. For several days in succession the Romans offered battle, but the Suevi refused to leave their strong position. This hesitation seemed remarkable, until it was explained by some prisoners, captured in a skirmish, who stated that the German priestesses had prophesied misfortune to Ariovistus, if he should fight before the new moon. Cæsar, thereupon, determined to attack the German camp without delay. The meeting of the two armies was fierce, and the soldiers were soon fighting hand to hand. On each side one wing gave way, but the greater quickness and superior military skill of the Romans enabled them to recover sooner than the enemy. The day ended with the entire defeat of the Suevi, and the flight of the few who escaped across the Rhine. They did not attempt to reconquer their lost territory, and the three small German tribes, who had long been settled between the Rhine and the Vosges (in what is now Alsatia), became subject to Roman rule. Two years afterwards, Cæsar, who was engaged in subjugating the Belgæ, in Northern Gaul, learned that two other German tribes, the Usipetes and Tencteres, who had been driven from their homes by the Suevi, had crossed the Rhine below where Cologne now stands. They numbered 400,000, and the Northern Gauls, instead of regarding them as invaders, were inclined to welcome them as allies against Rome, the common enemy. Cæsar knew that if they remained, a revolt of the Gauls against his rule would be the consequence. He therefore hastened to meet them, got possession of their principal chiefs by treachery, and then attacked their camp between the Meuse and the Rhine. The Germans were defeated, and nearly all their foot-soldiers slaughtered, but the cavalry succeeded in crossing the river, where they were welcomed by the Sicambrians. Then it was that Cæsar built his famous wooden bridge across the Rhine, not far from the site of Cologne, although the precise point can not now be ascertained. He crossed with his army into Westphalia, but the tribes he sought retreated into the great forests to the eastward, where he was unable to pursue them. He contented himself with burning their houses and gathering their ripened harvests for eighteen days, when he returned to the other side and destroyed the bridge behind him. From this time, Rome claimed the sovereignty of the western bank of the Rhine to its mouth. [Sidenote: 53 B. C.]