At the same time, the two Emperors agreed to elevate their sons to the rank of Cæsar. Constantine bestowed the dignity upon Crispus, the son of his first marriage with Minervina. Crispus was now in the promise of early manhood, and had proved his valour, and won his spurs in the recent campaign. Licinius gave the title to his son Licinianus, an infant no more than twenty months old. These appointments are important, for they shew how completely the system of Diocletian had broken down. The Emperors appointed Cæsars out of deference to the letter of that constitution, but they outrageously violated its spirit by appointing their own sons, and when the choice fell on an infant, insult was added to injury. It was plain warning to all the world that Constantine and Licinius meant to keep power in their own hands. When, a few years later, three sons were born to Constantine and Fausta in quick succession, the eldest, who was given the name of his father, was created Cæsar shortly after his birth. No doubt the Empress—herself an Emperor’s daughter—demanded that her son should enjoy equal rank with the son of the low-born Minervina, and the probabilities are that Constantine already looked forward to providing the young Princes with patrimonies carved out of the territory of Licinius. However, there was no actual rupture between the two Emperors until 323, though relations had long been strained. We know comparatively little of what took place in the intervening years. They were not, however, years of unbroken peace. There was fighting both on the Danube and the Rhine. The Goths and the Sarmatæ, who had been taught such a severe lesson by Claudius and Aurelian that they had left the Danubian frontier undisturbed for half a century, again surged forward and swept over Moesia and Pannonia. We hear of several hard-fought battles along the course of the river, and then, when Constantine, at the head of his legions, had driven out the invader, he himself crossed the Danube and compelled the barbarians to assent to a peace whereby they pledged themselves to supply the Roman armies, when required, with forty thousand auxiliaries. The details of this campaign are exceedingly obscure and untrustworthy. The Panegyrists of the Emperor claimed that he had repeated the triumphs of Trajan. Constantine himself is represented by the mocking Julian as boasting that he was a greater general than Trajan, because it is a finer thing to win back what you have lost than to conquer something which was not yours before. The probabilities are that there took place one of those alarming barbarian movements from which the Roman Empire was never long secure, that Constantine beat it back successfully, and gained victories which were decisive enough at the moment, but in which there was no real finality, because no finality was possible. Probably it was the seriousness of these Gothic and Sarmatian campaigns which was chiefly