Within a few days Galerius Cæsar arrived, not to congratulate his father-in-law on the re-establishment of his health, but to force him to resign the empire. Already he had urged Maximian Herculius to the like purpose, and by the alarm of civil wars terrified the old man into compliance; and he now assailed Diocletian. At first, in gentle and friendly terms, he said that age and growing infirmities disabled Diocletian for the charge of the commonweal, and that he had need to give himself some repose after his labours. Galerius, in confirmation of his argument, produced the example of Nerva, who laid the weight of empire on Trajan.
But Diocletian made answer, that it was unfit for one who had held a rank, eminent above all others and conspicuous, to sink into the obscurity of a low station; neither indeed was it safe, because in the course of so long a reign he must unavoidably have made many enemies. That the case of Nerva was very different: he, after having reigned a single year, felt himself, either from age or from inexperience in business, unequal to affairs so momentous, and therefore threw aside the helm of government, and returned to that private life in which he had already grown old. But Diocletian added, that if Galerius wished for the title of emperor, there was nothing to hinder its being conferred on him and Constantius, as well as on Maximian Herculius.
Galerius, whose imagination already grasped at the whole empire, saw that little but an unsubstantial name would accrue to him from this proposal, and therefore replied that the settlement made by Diocletian himself ought to be inviolable; a settlement which provided that there should be two of higher rank vested with supreme power, and two others of inferior, to assist them. Easily might concord be preserved between two equals, never amongst four; that he, if Diocletian would not resign, must consult his own interests, so as to remain no longer in an inferior rank, and the last of that rank; that for fifteen years past he had been confined, as an exile, to Illyricum and the banks of the Danube, perpetually struggling against barbarous nations, while others, at their ease, governed dominions more extensive than his, and better civilized.
Diocletian already knew, by letters from Maximian Herculius, all that Galerius had spoken at their conference, and also that he was augmenting his army; and now, on hearing his discourse, the spiritless old man burst into tears, and said, “Be it as you will.”
It remained to choose Cæsars by common consent. “But,” said Galerius, “why ask the advice of Maximian and Constantius, since they must needs acquiesce in whatever we do?”—“Certainly they will,” replied Diocletian, “for we must elect their sons.”
Now Maximian Herculius had a son, Maxentius, married to the daughter of Galerius, a man of bad and mischievous dispositions, and so proud and stubborn withal, that he would never pay the wonted obeisance either to his father or father-in-law, and on that account he was hated by them both. Constantius also had a son, Constantine, a young man of very great worth, and well meriting the high station of Cæsar. The distinguished comeliness of his figure, his strict attention to all military duties, his virtuous demeanour and singular affability, had endeared him to the troops, and made him the choice of every individual. He was then at court, having long before been created by Diocletian a tribune of the first order.