GALERIUS MAXIMIANUS (C. Galerius Valerius Maximianus Augustus). — Roman emperor, born in Illyricum around the mid-3rd century, died in Nicomedia in May 311. Of humble origins, he was a wild, coarse, ignorant, cruel, and brutish man; tall in stature, he inspired terror in all. He distinguished himself in the army and on 10 March 293, in the tetrarchy created by Diocletian, was appointed Caesar for the East, with residence in Sirmium and jurisdiction over Macedonia, Epirus, Achaea, Illyricum, and the Danubian provinces. He then married Valeria, Diocletian’s daughter. He conducted a series of victorious campaigns against the barbarians pressing on the empire’s borders along the Danube; in 297 he won a splendid victory over the Persians, and in 299 over the Marcomanni and the Sarmatians. He then became arrogant and domineering, completely dominating the weak character of Diocletian. Urged on by his mother Romula, a fervent pagan, superstitious and bitterly hostile to Christians, he became the principal promoter of the persecution against them. Even after the Persian victory, he began purging Christians from the army and the court.
At the beginning of 303 he went to Nicomedia, and after a series of secret meetings with Diocletian succeeded in having the first edict of persecution promulgated (February 303), which ordered the destruction of churches and the burning of sacred books. A double fire broke out in the imperial palace within a few days; Galerius managed to shift the blame onto the Christians and extract from the exasperated Diocletian three further bloody edicts of persecution (303–304). Eager to wield ever greater power, he forced the old Diocletian to abdicate, and on 19 May 305 assumed the title and office of Augustus. He then displayed all his sanguinary cruelty, persecuting Christians with even greater fury. But his plans for absolute domination were shattered in 305 when, following the death of Constantius Chlorus, his son Constantine was acclaimed Augustus by the soldiers. Increasingly suspicious and cruel, he degraded and tortured officials and magistrates, punishing with torture, fire, and exposure to beasts anyone suspected of disloyalty; he humiliated noble matrons and subjected his subjects to heavy taxation. Meanwhile, the tetrarchy created by Diocletian was collapsing amid the rise of rival emperors; to punish the rebel Maxentius, in 307 Galerius attempted to occupy Rome, but abandoned by his troops, he had to retreat. In 310 he was struck by a terrible illness, which made his body cancerous and teeming with worms. All remedies proved useless; recognizing that he was being punished by God, in early April 311 he issued a decree granting Christians the right to exist and to rebuild their churches, openly acknowledging the failure of his persecution. A few days later he died in terrible agony.