About this time Constantine the Great, who was previously a man of no religion, is said to have embraced Christianity, being induced thereto principally by the miracle of a cross appearing to him in the heavens. But this story is liable to much doubt. His first edict in favor of the Christians, and many other things, sufficiently evince that he was indeed at that time well disposed toward the Christians and their worship, but that he by no means regarded Christianity as the only true and saving religion; on the contrary, it appears that he regarded other religions, and among them the old Roman religion, as likewise true and useful to mankind; and he therefore wished all religions to be freely practised throughout the Roman Empire. But as he advanced in life, Constantine made progress in religious knowledge, and gradually came to regard Christianity as the only true and saving religion, and to consider all others as false and impious. Having learned this, he now began to exhort his subjects to embrace Christianity; and at length he proclaimed war against the ancient superstitions. At what time this change in the views of the Emperor took place, and he began to look upon all religions but the Christian as false, cannot be determined. This, however, is certain, that the change in his views was first made manifest by his laws and edicts in the year 324, after the death of Licinius, when Constantine became sole emperor. His purpose, however, of abolishing the ancient religion of the Romans, and of tolerating only the Christian religion, he did not disclose till a little before his death, when he published his edicts for pulling down the pagan temples and abolishing the sacrifices.
That the Emperor was sincere, and not a dissembler, in regard to his conversion to Christianity, no person can doubt who believes that men's actions are an index of their real feelings. It is indeed true that Constantine's life was not such as the precepts of Christianity required; and it is also true that he remained a catechumen all his life, and was received to full membership in the Church, by baptism, only a few days before his death, at Nicomedia. But neither of these is adequate proof that the Emperor had not a general conviction of the truth of the Christian religion, or that he only feigned himself a Christian. For in that age many persons deferred baptism till near the close of life, that they might pass into the other world altogether pure and undefiled with sin; and it is but too notorious that many persons who look upon the Christian religion as indubitably true and of divine origin, yet do not conform their lives to all its holy precepts. It is another question whether worldly motives might not have contributed in some degree to induce Constantine to prefer the Christian religion to the ancient Roman, and to all other religions, and to recommend the observance of it to his subjects. Indeed, it is no improbable conjecture that the Emperor had discernment to see that Christianity possessed great efficacy, and idolatry none at all, to strengthen public authority, and to bind citizens to their duty.
The sign of the cross, which Constantine most solemnly affirmed he saw in the heavens, near midday, is a subject involved in the greatest obscurities and difficulties. It is, however, an easy thing to refute those who regard this prodigy as a cunning fiction of the Emperor, or who rank it among fables; and also those who refer the phenomenon to natural causes, ingeniously conjecturing that the form of a cross appeared in a solar halo, or in the moon; and likewise those who ascribe the transaction to the power of God, who intended by a miracle to confirm the wavering faith of the Emperor. Now these suppositions being rejected, the only conclusion that remains is that Constantine saw, in a dream while asleep, the appearance of a cross, with the inscription, In hoc signo vinces ("By this sign thou shalt conquer"). Nor is this opinion unsupported by competent authorities of good credit.
The happiness anticipated by the Christians from the edicts of Constantine and Licinius was a little afterward interrupted by Licinius, who waged war against his kinsman Constantine. Being vanquished in the year 314, he was quiet for about nine years. But in the year 324 this restless man again attacked Constantine, being urged on both by his own inclination and by the instigation of the pagan priests. That he might secure himself a victory, he attached the pagans to his cause by severely oppressing the Christians, and putting not a few of their bishops to death. But all his plans failed; for, after several unsuccessful battles, he was obliged to throw himself upon the mercy of the victor, who, nevertheless, ordered him to be strangled, in the year 325. After his victory over Licinius, Constantine reigned sole emperor till his death; and by his plans, his enactments, his regulations, and his munificence he endeavored as much as possible to obliterate gradually the ancient superstitions and to establish Christian worship throughout the Roman Empire. He had undoubtedly learned from the wars and the machinations of Licinius that neither himself nor the Roman Empire could remain secure while the ancient superstition continued prevalent; and therefore, from this time onward, he openly opposed the pagan deities and their worship, as being prejudicial to the interests of the State.
After the death of Constantine, which happened in the year 337, his three surviving sons, Constantine II, Constantius, and Constans, assumed the empire, and were all proclaimed emperors by the Roman senate. There were still living two brothers of Constantine the Great, namely, Constantius Dalmatius and Julius Constans, and they had several sons. But nearly all of these were slain by the soldiers at the command of Constantine's sons, who feared lest their thirst for power might lead them to make insurrections and disturb the Commonwealth. Only Gallus and Julian, sons of Julius Constans, escaped the massacre; and the latter of these afterward became emperor. Constantine II held Britain, Gaul, and Spain, but lost his life, a.d. 340, in a war with his brother Constans, who at first governed only Illyricum, Italy, and Africa; but after the fall of his brother, Constantine II, he annexed his provinces to his empire, and thus became emperor of all the West, until he lost his life, a.d. 350, in the war with Maxentius, a usurper. After the death of Constans, Maxentius being subdued, the third brother, Constantius, who had before governed Asia, Syria, and Egypt, in the year 353 became sole emperor, and governed the whole empire till the year 361, when he died. Neither of these brothers possessed the disposition or the discernment of their father; yet they all pursued their father's purpose of abolishing the ancient superstitions of the Romans and other pagans, and of propagating the Christian religion throughout the Roman Empire. The thing itself was commendable and excellent; but in the means employed there was much that was censurable.
Rhetoricians and philosophers, whose schools were supposed to be so profitable to the community, exhausted all their ingenuity, both before the days of Constantine the Great and afterward, to arrest the progress of Christianity. In the beginning of this century Hierocles, the great ornament of the Platonic school, composed two books against the Christians, in which he had the audacity to compare our Saviour with Apollonius Tyanæus, and for which he was chastised by Eusebius in a tract written expressly against him. Lactantius speaks of another philosopher who endeavored to convince the Christians they were in error; but his name is not mentioned. After the reign of Constantine the Great, Julian wrote a large volume against the Christians, and Himerius and Libanius in their public declamations, and Eunapius in his lives of the philosophers, zealously decried the Christian religion. Yet no one of these persons was punished at all for the licentiousness of his tongue or of his pen.
How much harm these sophists or philosophers, who were full of the pride of imaginary knowledge and of hatred to the Christian name, did to the cause of Christianity in this century appears from many examples, and especially from the apostasy of Julian, who was seduced by men of this stamp. Among those who wished to appear wise, and to take moderate ground, many were induced by the arguments and explanations of these men to devise a kind of reconciling religion, intermediate between the old superstition and Christianity, and to imagine that Christ had enjoined the very same thing which had long been represented by the pagan priests under the envelope of their ceremonies and fables. Of these views were Ammianus Marcellinus, a very prudent and discreet man; Chalcidius, a philosopher; Themistius, a very celebrated orator, and others, who conceived that both religions were in unison, as to all the more important points, if they were rightly understood, and therefore held that Christ was neither to be contemned nor to be honored to the exclusion of the pagan deities.
As Constantine the Great and his sons and successors took much pains to enlarge the Christian Church, it is not strange that many nations, before barbarous and uncivilized, became subject to Christ. Many circumstances make it probable that the light of Christianity cast some of its rays into both Armenias, the Greater and the Less, soon after the establishment of the Christian Church. But the Armenian Church first received due organization and firm establishment in this century; in the beginning of which Gregory, the son of Anax, commonly called "the Illuminator," because he dispelled the mists of superstition which beclouded the minds of the Athenians, first persuaded some private individuals, and afterward Tiridates, the king of the Armenians, as well as his nobles, to embrace and observe the Christian religion. He was therefore ordained the first bishop of Armenia, by Leontius, bishop of Cappadocia, and gradually diffused the principles of Christianity throughout that country.
In the European provinces of the Roman Empire there still remained a vast number of idolaters; and though the Christian bishops endeavored to convert them to Christ, the business went on but slowly. In Gaul, the great Martin, bishop of Tours, was not unsuccessful in this work; but travelling through the provinces of Gaul, he everywhere persuaded many to renounce their idols and embrace Christ, and he destroyed their temples and threw down their statues. He therefore merited the title "Apostle of the Gauls."
It is very evident that the victories of Constantine the Great, and both the fear of punishment and the desire of pleasing the Roman emperors, were cogent reasons, in the view of whole nations as well as of individuals, for embracing the Christian religion. Yet no person well informed in the history of this period will ascribe the extension of Christianity wholly to these causes. For it is manifest that the untiring zeal of the bishops and other holy men, the pure and devout lives which many of the Christians exhibited, the translations of the sacred volume, and the excellence of the Christian religion were as efficient motives with many persons as the arguments from worldly advantage and disadvantage were with some others.