Galerius Maximianus (c. 250 - 5 May, 311), formally Gaius Galerius Valerius Maximianus, Roman emperor from 305 to 311, was born on a small farm estate, on the site where he later built his palace, Felix Romuliana. His father was a Thracian and his mother Romula was a Dacian woman. He originally followed his father's occupation, that of a herdsman, where he got his surname of Armentarius (Lat. armentum, herd). He served with distinction as a soldier under Aurelian and Probus, and in 293 at the establishment of the Tetrarchy, was designated Caesar along with Constantius Chlorus, receiving in marriage Diocletian's daughter Valeria (later known as Galeria Valeria), and at the same time being entrusted with the care of the Illyrian provinces.
In 296, at the beginning of the Persian War, he was removed from the Danube to the Euphrates; his first campaign ended in a crushing defeat, near Callinicum, which lost Mesopotamia to Rome. However, in 297, advancing through the mountains of Armenia, he gained a decisive victory over Narses, with an enormous amount of booty that included Narses' harem. Following up his advantage, he took the city of Ctesiphon and in 298 Narses sued for peace. Mesopotamia was returned to Roman rule and even some territory east of the Tigris, which marks the greatest extension of the Roman Empire in the east.
Christians had lived in peace during most of the rule of Diocletian. The persecutions that began with an edict of February 24, 303, were credited by Christians to the influence of Galerius. Christian houses of assembly were destroyed, for fear of sedition in secret gatherings. Image:Thessaloniki-Arch of Galerius (detail).jpg
In 305, on the abdication of Diocletian and Maximian, he at once assumed the title of Augustus, with Constantius his former colleague, and having procured the promotion to the rank of Caesar of Flavius Valerius Severus, a faithful servant, and (Maximinus II Daia), his nephew, he hoped on the death of Constantius to become sole master of the Roman world. Having Constantius' son Constantine as guest at Galerius' court in the east helped to secure his position.
His schemes, however, were defeated by the sudden elevation of Constantine at Eboracum upon the death of his father, and by the action of Maximianus and his son Maxentius, who were declared co-Augusti in Italy.
After an unsuccessful invasion of Italy in 307, he elevated his friend Licinius to the rank of Augustus, and moderating his ambition, devoted the few remaining years of his life "to the enjoyment of pleasure and to the execution of some works of public utility."
It was at the instance of Galerius that the last edicts of persecution against the Christians were published, beginning on February 24, 303, and this policy of repression was maintained by him until the appearance of the general edict of toleration, issued from Nicomedia in April 311, apparently during his last bout of illness, in his own name and in those of Licinius and Constantine. Lactantius gives the text of the edict in his moralized chronicle of the bad ends to which all the persecutors came, De Mortibus Persecutorum ("On the Deaths of the Persecutors", chapters 34, 35). This marked the end of official persecution of Christians.
According to Lactantius, Galerius had affirmed his Dacian identity, and 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 - exhibiting an anti-Roman attitude as soon as he had attained the highest power, treating the Roman citizens with ruthless cruelty, like the conquerors treated the conquered, all in the name of the same treatment that the victorious Trajan had applied to the conquered Dacians (forefathers of Galerius), two centuries before.
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 Data, 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 mined 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. full translation here
Galerius died on 5 May, 311 from complications of a rare disease in which worms were consuming his inner organs.
Galerius is remembered in Romanian religious-folk songs as Ler Imparat (Emperor Ler).