The first of these emperors who was disposed of was Maximian, the father of Maxentius and father-in-law of Constantine.  He was regarded as a usurper, and on the capture of Marseilles, he under pressure of Constantine committed suicide by strangulation, A.D. 310.  Galerius did not long survive, being afflicted with a loathsome disease, the result of intemperance and gluttony, and died in his palace in Nicomedia, in Bithynia, the capital of the Eastern provinces.  The next emperor who fell was Maxentius, after a desperate struggle in Italy with Constantine,—­whose passage over the Alps, and successive victories at Susa (at the foot of Mont Cenis, on the plains of Turin), at Verona, and Saxa Rubra, nine miles from Rome, from which Maxentius fled, only to perish in the Tiber, remind us of the campaigns of Hannibal and Napoleon.  The triumphal arch which the victor erected at Rome to commemorate his victories still remains as a monument of the decline of Art in the fourth century.  As a result of the conquest over Maxentius, the Praetorian guards were finally abolished, which gave a fatal blow to the Senate, and left the capital disarmed and exposed to future insults and dangers.

The next emperor who disappeared from the field was Maximin, who had embarked in a civil war with Licinius.  He died at Tarsus, after an unsuccessful contest, A.D. 313; and there were left only Licinius and Constantine,—­the former of whom reigned in the East and the latter in the West.  Scarcely a year elapsed before these two emperors embarked in a bloody contest for the sovereignty of the world.  Licinius was beaten, but was allowed the possession of Thrace, Asia Minor, Syria, and Egypt.  A hollow reconciliation was made between them, which lasted eight years, during which Constantine was engaged in the defence of his empire from the hostile attacks of the Goths in Illyricum.  He gained great victories over these barbarians, and chased them beyond the Danube.  He then turned against Licinius, and the bloody battle of Adrianople, A.D. 323, when three hundred thousand combatants were engaged, followed by a still more bloody one on the heights of Chrysopolis, A.D. 324, made Constantine supreme master of the Empire thirty-seven years after Diocletian had divided his power with Maximian.

The great events of his reign as sole emperor, with enormous prestige as a general, second only to that of Julius Caesar, were the foundation of Constantinople and the establishment of Christianity as the religion of the Empire.

The ancient Byzantium, which Constantine selected as the new capital of his Empire, had been no inconsiderable city for nearly one thousand years, being founded only ninety-seven years after Rome itself.  Yet, notwithstanding its magnificent site,—­equally favorable for commerce and dominion,—­its advantages were not appreciated until the genius of Constantine selected it as the one place in his vast dominions which combined a central position and capacities