Caesar replied that they must not stay in Gaul. There were no unoccupied lands in Gaul which could receive so vast a multitude. The Ubii[1] on their own side of the Rhine were allies of the Romans; the Ubii, he was willing to undertake, would provide for them; meanwhile they must go back; he would listen to no other conditions. The envoys departed with their answer, begging Caesar to advance no farther till he had again heard from them. This could not be granted. The interval would be employed in communicating with the Gauls. Caesar pushed on, crossed the Meuse at Maestricht, and descended the river to Venloo, where he was but twelve miles distant from the German head-quarters. Again messengers came, asking for time--time, at least, till they could learn whether the Ubii would receive them. If the Ubii were favorable, they said that they were ready to go; but they could not decide without a knowledge of what was to become of them. They asked for a respite, if only for three days. Three days meant only leisure to collect their scattered detachments, that they might make a better fight. Caesar gave them twenty-four hours. The two armies were so near that their front lines were in sight of each other. Caesar had given orders to his officers not to meddle with the Germans. But the Germans, being undisciplined and hot-blooded, were less easy to be restrained. A large body of them flung themselves on the Roman advanced guard, and drove it in with considerable loss; seventy-four Roman knights fell, and two Aquitanian noblemen, brothers, serving under Caesar, were killed in defending each other.