227. The next year, A. D. 305, Diocletian, worn out with the cares of empire, formally abdicated his power, and compelled Maximian to do the same. The two Cæsars now became Augusti, and two new candidates, Maximin and Severus, were appointed by Galerius to the former title. The legions in Britain were dissatisfied, however, by seeing the choice of a successor taken away from their own imperator; and upon the death of Constantius, A. D. 306, they immediately proclaimed Con´stantine, his son. He was acknowledged as Cæsar by Galerius, who conferred the rank of Augustus on Severus.
But, the next year, Maxen´tius, son of Maximian, was declared emperor by the Senate and people of Rome, and his father resumed the purple, which he had unwillingly laid aside at the command of Diocletian. Severus, attempting to crush this insurrection, was taken captive at Ravenna, and privately put to death. Galerius now conferred the imperial dignity on Licinius, and for two years the Roman world was peaceably governed by six masters: Constantine, Maximian, and Maxentius in the West; Galerius, Maximin, and Licinius in the East.
228. The peace was first broken by the dissensions of Maximian and his son. The elder emperor fled from Rome, and was well received by Constantine, who had married his daughter. Before long, however, Maximian entered again into plots with Maxentius for the ruin of Constantine; which becoming known to their intended victim, he returned promptly from his campaign on the Rhine, besieged his father-in-law in Massilia, and put him to death, A. D. 310. Galerius died the next year at Nicomedia, and the empire was again divided into four parts, of which Constantine ruled the extreme west; Maxentius, Italy and Africa; Licinius, Illyricum and Thrace; Maximin, Egypt and Asia.
The cruel and rapacious character of Maxentius wearied out his subjects, who sent deputies from Rome, beseeching Constantine to come and be their sovereign. This great general had won the love of his followers, not less by his firm and successful dealings with the barbarians, than by his liberal protection of the Christians, whose virtues he esteemed, and whose rights of conscience he respected. On his march toward Italy, it is said that he beheld a vision. A flaming cross appeared in the heavens, bearing in Greek the inscription, “By this, conquer!” Thenceforth, the cross replaced the pagan symbols which had been carried at the head of the legions; and the omen, if such it was, was amply fulfilled.
229. Constantine passed the Alps, A. D. 312, defeated the troops of Maxentius near Turin, captured Verona after an obstinate siege and battle, and encountered his rival in a final combat before the gates of Rome. In the battle of the Mil´vian Bridge, Maxentius was defeated and drowned. The following year, Maximin was defeated by Licinius, in a great battle at Heraclea, on the Propontis, and put an end to his life at Tarsus, in Cilicia. Constantine and Licinius, in a series of battles, divided the world between them. The river Strymon and the Ægean became the boundaries between the Eastern and Western empires. Two sons of Constantine and one of Licinius received the title of Cæsar. Crispus, on the Rhine, gained a victory over the Franks and Alemanni; and Constantine, on the Danube, executed a terrible vengeance upon the Goths, who had invaded the Roman territory.
230. After seven years’ peace, war broke out between the emperors, in A. D. 322. Licinius was defeated near Hadriano´ple, besieged in Byzantium, and finally overthrown upon the Heights of Scuta´ri, overlooking the latter city. His death made Constantine the sole ruler of the civilized world. His great dominion received a new constitution suitable to its magnitude. The seat of government was fixed upon the confines of Europe and Asia, in the new and magnificent city bearing the emperor’s name, which he built upon the ruins of the Greek Byzantium. The whole empire was divided into four præfectures, which nearly corresponded to the dominions of the four emperors, A. D. 311. ([§ 228.]) Each præfecture was divided into dioceses, and each diocese into proconsular governments, or presidencies.
This subdivision of the empire gave rise to three ranks of officials, somewhat resembling the nobility of modern Europe. The republican form of government, so ostentatiously cherished by Augustus, had now disappeared, and in its place was the elaborate ceremony of an Oriental court. Even the 10,000 spies, known as the “King’s Eyes,” were maintained as of old by Xerxes and Darius. A standing army of 645,000 men was kept upon the frontier; but as Roman citizens were now averse to military service, the legions were largely composed of barbarian mercenaries. The Franks, especially, had great importance, both in the court and camp of Constantine.
231. The great event of this reign was the admission of Christianity as, in a certain sense, the religion of the state. The Edict of Milan, A. D. 313, guaranteed to the hitherto persecuted people perfect security and respect; that of A. D. 324 exhorted all subjects of the empire to follow the example of their sovereign, and become Christians. Heathenism was not yet proscribed. Constantine was pontifex maximus, and must, on certain occasions, have offered sacrifices to the fabulous gods of Rome. It was only in his last days that he received Christian baptism; but he presided in the first General Council of the Church at Nice, in Bithynia, A. D. 325, to which he had convened bishops from all parts of the empire, to decide certain disputed matters of faith. Though he treated the assembled fathers with every mark of reverence, he refused to persecute Arius and his followers, the Alexandrian heretics, whom the Council condemned.
232. Crispus, the eldest son of Constantine, who had been named Cæsar at the age of seventeen, was the idol of the people, but an object of jealousy to his father, who suspected him of treasonable designs. Whether the charges against him were true, we have no means of knowing. He was seized during the festivities in Rome, in honor of the twentieth year of his father’s reign, tried secretly, and put to death. The last years of Constantine were disturbed by fresh movements of the barbarians north of the Danube. The Sarmatians, being attacked by the Goths, implored the aid of the Romans. Constantine was defeated in one battle with the invaders, but in the next he was victorious, and 100,000 Goths, driven into the mountains, perished with cold and hunger. In the division of spoils, the Sarmatians were dissatisfied, and revenged themselves by making inroads upon the Roman dominions. In succeeding wars they were defeated and scattered; 300,000 were received as vassals of the empire, and settled in military colonies in Pannonia, Thrace, Macedonia, and Italy.