Ante-Nicene Fathers, Vol VII:
Lactantius: Chap. XXVII

Chap. XXVII.

But Maximian, who knew the outrageous temper of Galerius, began to consider that, fired with rage on hearing of the death of Severus, he would march into Italy, and that possibly he might be joined by Daia, and so bring into the field forces too powerful to be resisted. Having therefore fortified Rome, and made diligent provision for a defensive war, Maximian went into Gaul, that he might give his younger daughter Fausta in marriage to Constantine, and thus win over that prince to his interest. Meantime Galerius assembled his troops, invaded Italy, and advanced towards Rome, resolving to extinguish the senate and put the whole people to the sword. But he found everything shut and fortified against him. There was no hope of carrying the place by storm, and to besiege it was an arduous undertaking; for Galerius had not brought with him an army sufficient to invest the walls. Probably, having never seen Rome, he imagined it to be little superior in size to those cities with which be was acquainted. But some of his legions, detesting the wicked enterprise of a father against his son-in-law, and of Romans against Rome, renounced his authority, and carried over their ensigns to the enemy. Already had his remaining soldiers begun to waver, when Galerius, dreading a fate like that of Severus, and having his haughty spirit broken and humiliated, threw himself at the feet of his soldiers, and continued to beseech them that he might not be delivered to the foe, until, by the promise of mighty largesses, he prevailed on them. Then he retreated from Rome, and fled in great disorder. Easily might he have been cut off in his flight, had any one pursued him even with a small body of troops. He was aware of his danger, and allowed his soldiers to disperse themselves, and to plunder and destroy far and wide, that, if there were any pursuers, they might be deprived of all means of subsistence in a ruined country. So the parts of Italy through which that pestilent band took its course were wasted, all things pillaged, matrons forced, virgins violated, parents and husbands compelled by torture to disclose where they had concealed their goods, and their wives and daughters; flocks and herds of cattle were driven off like spoils taken from barbarians. And thus did he, once a Roman emperor, but now the ravager of Italy, retire into his own territories, after having afflicted all men indiscriminately with the calamities of war. Long ago, indeed, and at the very time of his obtaining sovereign power, he had avowed himself the enemy of the Roman name; and he proposed that the empire should be called, not the Roman, but the Dacian empire.