3Then the Cæsar, like an experienced general, fearing that the barbarians might take advantage of some moonless night to cross over the river, which was now thoroughly frozen, ordered soldiers to go up and down the stream every day in light boats, from sunset till daybreak, so as to break the crust of ice and prevent any one from escaping in that manner. Owing to this manœuvre, the barbarians were so exhausted by hunger, watching, and the extremity of despair, that at last they voluntarily surrendered, and were immediately sent to the court of the emperor.