MASSIMINO Daia (Galerius Valerius Maximinus Daia), ROMAN EMPEROR. – Son of a sister of Galerius (v.), born in Illyricum, he was supported by his uncle in his military career and subsequently adopted, taking the names Galerius Valerius M. The form D. of the surname seems, on epigraphic evidence, preferable to the other form, Daza (v. , e.g., CIL, VIII, 10784).
On the day of the abdication of Diocletian and Maximian (1 May 305), when the Caesars Galerius and Constantius Chlorus were promoted to Augusti, M. D. was appointed Caesar together with Flavius Severus. He was assigned the two dioceses of the East and Egypt. From the outset his inadequacy was so evident that at the conference of Carnuntum, held under the presidency of Diocletian (308), he was not, as he ought to have been, promoted from Caesar to Augustus; instead, a « homo novus », Licinius, was preferred to him. This slight brought him fatally closer to another rejected man, Maxentius, although their friendship could not be translated into any effective action, since each was absorbed by his own difficulties. When Galerius died (311), M. had himself acclaimed Augustus by his own soldiers and hastened to occupy the whole of Asia Minor. His army and that of Licinius stood arrayed against each other on the shores of the Bosporus, but since neither felt certain of being able to win, no battle took place. In 312, held back by threats from Armenia, M. was unable to bring aid to Maxentius against Constantine. When, however, after Constantine’s victory, Licinius went to Milan and married the victor’s sister, M. judged that he could cross the Bosporus, and occupied Byzantium and Heraclea. This time, however, Licinius could not remain inactive; battle was joined at Campus Serenus near Heraclea, and M. was completely defeated. He fled through Asia Minor and tried to gather additional forces, but, stricken by illness, died at Tarsus in Cilicia in the autumn of 313 (on 26 November of that year his third consulship is recorded as cancelled in Egyptian documents: Berliner Aegyptische Urkunden, I, 349). He was always hostile to the Christians, a zealous executor of Diocletian’s edict of persecution and reluctant to apply Galerius’s edict of toleration.