It was on his way to this decisive battle that Constantine was suddenly converted.

Our knowledge of the event comes mainly from Eusebius of Cæsarea, the preacher of the sermon at he consecration of the church in Tyre, who was informed by Constantine himself. On a day in October, 312, Constantine with his army was making his difficult way over the Alps. In the blaze of noon, "he saw with his own eyes," says Eusebius, "the trophy of a cross of light in the heavens, above the brightness of the sun, and bearing the inscription, 'By this conquer' ( )." That night Christ appeared in a dream and told him to make a likeness of the celestial cross as a protection against his enemies. This he did in the form of a monogram of the first two letters of the name Christ in Greek ( ), and under banners and behind shields thus emblazoned he marched to victory.

That the course of history has been determined on several occasions by the experience of a vision is a phenomenon which is substantially attested. Saul of Tarsus saw a strange sight on the road to Damascus, and was changed thereby from a purpose to persecute the Christians to a position of singularly influential leadership among them. Augustine heard a sound of words at Milan which suddenly brought him out of indifference and doubt into a faith which mightily affected Christian theology for a thousand years, and affects it still.

A vision however, is only part a matter of the senses. Whatever the external facts may be, the determining sight is seen with the eyes of the mind, and the determining words are heard with the hearing of the mind. And the mind sees and hears what it brings of sight and hearing. And this depends on the preparation of previous thought and experience. So it was in Saul. The vision seemed as sudden as a flash of lighting; but the suddenness of lighting is only in appearance, it is the result of a long and gradual assembling of forces. The whole life of Saul had made him ready for that day. So it was with Constantine.

Diocletian, in his reorganization of the empire, had found himself confronted by the Christians. They made up one twelfth of the population, and their influence was out of all proportion to their number. They were constantly enlisting the allegiance of men of outstanding character and ability. It was plain to the emperor that he must either be the head of the Christina Church or its destroyer. He resolved to destroy it.

With this resolution the father of Constantine was not in sympathy. Constantius took such part in the general persecution as the necessities of his position demanded, but in his portion of the empire the campaign was not carried on with rigor. The young prince, his son, shared his father's counsels, and partook of his spirit.

The event had revealed the folly of Diocletian, and had justified the wisdom of Constantius. It had proved, by the hard test of persecution, that the church could not be destroyed. The alternative, then, was alliance. He who would be master of Rome,—so it appeared to the clear mind of Constantine, —must have the Christians on his side.

With these thoughts in his heart, at a critical moment in his life, on the eve of a battle the object of which was to gain the Roman throne, Constantine saw a shining object in the sky which he perceived to be the Cross of Christ.

The conversion of Constantine was at the same time a victory for Christianity and a defeat. The new religion triumphed with the converted emperor. The edict of toleration which was issued in 313 put a definite end to persecution. Thenceforth the Roman world which had been officially pagan was officially Christian. But it was like the triumph of the Romans over the Greeks, wherein the Romans held the power of position, but the Greeks retained the power of influence. The world against which the saints had protested came into alliance with the church. The current standards of life lowered the Christian standards. The current philosophy affected the Christian theology.

We stand with Constantine where two rivers meet. One is the Christian river, having its rise in Judaism, bringing down Jewish and Christian elements together. The other is the pagan river, formed from a hundred contributory streams, bringing myths and legends, ceremonies of worship, mysteries, gods and goddesses, ancient customs, ancient interpretations of the world. At this point the rivers join to form the Church Catholic, from this moment a world of religion, Christian and pagan, having its source no longer in Jerusalem and in Antioch alone, but in the springs of all the hills of history, and in the brooks which flow though all the valleys of the past. The conversion of Constantine diverted not only the Jordan and the Orontes, but the Euphrates and the Tigris, and the Nile, the Danube and the Rhine, and made them flow into the channel of the Tiber.

The first rush of the new current endangered not only the morals but the essential beliefs of Christians. It was by no accidental coincidence that he Edict of Toleration was speedily followed by the Arian Debate.

The central assertion of all advanced philosophy and religion is the assertion of the unity of God. In the fourth century it was a commonplace of educated thought. Behind the Gods was god.

But pagan philosophers were denying either the personality or the presence of God. The Epicureans and the Stoics denied His personality, Him identical with Chance or Fate, and the Gnostics and the Neoplatonists were denying His presence, conceiving of Him as infinitely removed from the affairs of the world. Pagan priests were indeed ministering to the instinct which craves relationship with God. Mithraism was providing in Mithra a mediator between God and man. But Mithra was a celestial figure whose only dwelling was in a Persian dream. He had no actual existence.

The characteristic assertion of Christianity was the declaration of the divinity of Christ. Here, they said, is the true bond of union between God and man, in Him who is at the same time God and man.

The first task of Christian theologians had been that of affirmation: thus they had met the Ebionites, who denied the divinity of Jesus, and maintained that he was only a man like us. And thus they had met the Docetics, who denied the humanity of Jesus, holding that his human form and life were not in reality but only in appearance. These affirmations they based, without much discussion, on the revelation contained in Holy Scripture.

But the taks of affirmation was followed of necessity by the task of interpretation. Admitting that the Scriptures assert the divinity of Christ, how, then, is the divine Christ related to the one only God? The Sabellians explained the relation as consisting in distinction of activity. When we think of God as the maker and maintainer of the universe, we call Him the Father; when we think of Him as in Christ for the redemption of mankind, we call Him the Son. God is eternally one and the same, but we speak of Him under different names. Against this explanation, however, there was general protest. Conservative theologians held that it destroyed the Christian religion by destroying the reality of Christ. Christ, according to this doctrine, was absorbed in God.

The discussion was at this stage of progress, with Sabellianism in common disfavor, when a clergyman in Alexandria publicly accused his bishop of holding the Sabellian heresy. The accusing clergyman was Arius, the rector of the Church of Baucalis, the largest in the city. He was sixty years of age, dignified in appearance, austere, and blameless in life, learned, eloquent and pious, the most popular of the Alexandrian clergy. The Son, said Arius, is not—as Bishop Alexander and the Sabellians falsely affirm—identical with the Father. How can a son be identical with a father? There is one God, the Father, from whom the Son is derived, and to whom the Son is inferior. The Father is the Creator, eternally existing, before all time; the Son is created—there was a time (if we may use the word "time" of conditions so infinitely remote)—there was a time when He was not.

Thus over against the endeavor of the Sabellians to reconcile the divinity of Christ with the unity of God by identification, appeared the endeavor of the Arians to reconcile the divinity of Christ with the unity of God by distinction.

Immediately the church in Alexandria was divided into two contending parties, some siding with Alexander, some with Arius. Alexander appealed to his neighbors, the bishops of Egypt, summoning a council by whose action Arius was excommunicated. Arius appealed to his friends among the bishops of Syria: Eusebius of Cæsarea, Eusebius of Nicomedia, influential persons in the Court of Constantine. By them he was sustained.

The subtlety of the question was equalled only by the fury with which it was discussed. The debate was conducted with the violence of a political convention. Everybody entered into it. Men who met to transact business neglected their bargaining to talk theology. If one said to the baker, "How much is the loaf?" he would answer, "The Son is subordinate to the Father." If one sent a servant on an errand, he would reply, "The Son arose out of nothing." Arius put his doctrine into verse, to popular tunes, and it was sung and whistled in the streets. The arguments were punctuated with fists and clubs.

The news of this dissension disturbed the Christian emperor. Hoping by his espousal of Christianity to unify the empire, he was distressed to find that the Christians were themselves divided. He wrote to Alexander and to Arius, with a natural misunderstanding of the seriousness of the matter, and urged them to be reconciled and keep the peace. Believe in God, he said, and do not disturb yourselves concerning questions which no man can answer. But the letter did not good; the strife continued and increased. At last the emperor, to regain peace, determined upon the wise expedient of a free and representative assembly. He would have a meeting and conference of the chief men of the Christian religion.

Thus was convened, in the early summer of 325, the Council of Nicæa.

Asia Minor, bounded on the north by the Black Sea and on the west by the Ægean, holds between the two, at its northwest corner, the Sea of Marmora,—the Propontis,—connected with the Black Sea by the Bosphorus, and with the Ægean by the Hellespont. Opening into the Propontis from the east are a bay and a lake. On the bay is Nicomedia, then the capital of the empire of the East, and the residence of Constantine; on the lake is Nicæa.

Over the long roads, from all directions, borne in conveyances provided by the emperor, came the bishops. The number of them is uncertain, though tradition finally placed it at three hundred and eighteen, attracted by the coincidence with the number of the armed servants whom Abraham took to rout the invading kings. Most of them were from the East; partly because the place of meeting was in that region, but partly also because the church was still an Eastern Church. The West was missionary ground. Moreover, the subject of discussion was congenial with the Easter mind; it was foreign to the practical interests of the West. The council was essentially an Eater conference. The discussions were carried on in Greek; the resulting creed was not only in Greek, but its distinctive words were found afterwards to be almost incapable of translation into Latin.

Indeed, of the three hundred bishops, only five are known to have come from Latin Christiandom: from Spain one—Hosius of Cordova, the emperor's "chaplain" in the West; form Carthage one—Cæcilian, who had contended with the Donatists; one from Calabria, one from Gaul, one from Pannonia.

But the Westerns were not missed in the throng of Easterns. From the cities which Paul had evangelized came the bishops of Greece and Asia Minor. One was Spyridion of Cyprus, a shepherd bishop, who in the intervals of his episcopal duties still watched his flock; a simple, homely man, whose embalmed body is to this day carried twice a year about the streets of Corfu in procession; one may still look upon the hands which signed the Nicene Creed. Another was Acesius, a stout separatists, who believed that only he and a few like-minded with him would be saved, to whom Constantine is reported to have said, "Acesius, plant a ladder and climb up into heaven by yourself." To this a pleasant legend adds St. Nicholas of Myra, patron of the festivities of Christmas, even Santa Claus himself, who appears in an ancient picture of the council in the act of giving Arius a great box on the ear.

From Syria came Eusebius of Cæsarea, the emperor's Eastern "chaplain," a great prelate and a fair historian, afterwards biographer of Constantine; and Eusebius of Nicomedia, and Eustathius of Antioch, and Bishop John from Persia; and Bishop Jacob of Mesopotamia, who had been a hermit, and still wore his cloak of goat's hair.

From Egypt came Potammon and Paphnutius, each of whom had lost an eye in the Diocletian persecution. Indeed, many of the bishops bore the honorable marks of torture. From Alexandria came the bishop, Alexander, bringing with him as chaplain and secretary a young deacon, named Athanasius. Also came the minister of the parish of Baucalis, the heretic Arius.

In the place of meeting long benches were set against the walls on either side, upon which sat the bishops with their attendant clergy. In the middle of the room upon a chair lay a copy of the Gospels, a symbol of the presence of Him in whose name for whose honor they were assembled. At the end of the room was a seat for the emperor. Silence was called as he approached; all rose as he entered. They said afterward that he looked like an angel from heaven. Indeed, to any eyes the face and figure of Constantine fitted his high position. He was tall and stalwart; his beard was short, his hair fell upon his shoulders; his purple robe of silk embroidered with gold and pearls; he wore his crown; his eyes, they said, flashed like the eyes of a lion. He seemed as much impressed by the situation as they were, being at first doubtful whether to stand or sit, till they beckoned to him to be seated. A speech of welcome and gratitude was made, a gracious response was returned, and the sessions of the council were formally begun.

How long the fathers sat in conference is not known; neither is there any satisfactory record of the progress of the debate.

It is remembered that early in the proceedings the emperor brought in a package of letters, and caused a fire to be made in the brazier in the hall, and burned the letters in the presence of the bishops. These, he said, are communications which you have sent to me making complaints and accusations one against another. He begged them to be brotherly, to put their bickering aside, and cultivate the virtues of peace.

As regards to the main purpose of their meeting, however, they seem to have been, for the most part, agreed. They found the doctrines of Arius novel and objectionable. It is said that when some of the songs of Arius were recited to the council, the bishops clapped their hands over their ears, and shut their eyes. Eusebius of Nicomedia presented a creed setting forth the Arian ideas, and it was torn in pieces. Arius appeared to have few friends.

When it came, however, to the formulation of an acceptable creed, much difficulty was encountered. The general church possessed no creed. There were many statements of beliefs, used mainly in the sacrament of baptism, expressing in a manner which gradually had approached to uniformity the mind of the church respecting matters which had been brought into controversy. In the West, the short formula called the Apostles' Creed had gained wide acceptance. In the East, the local creeds tended to greater length. Eusebius of Cæsarea recited one which was in common use in his diocese. It seemed to the fathers to be both true and sufficient. Indeed, they were on the point of accepting it, when they perceived that it was equally acceptable to the Arians.

With such condition of happy agreement a conference in search of working unity would have been satisfied. Within the safe limits of such an inclusive formula they would have been content to leave conflicting details for future peaceful settlement, or even to have permitted a difference of opinion regarding matters which seemed so far beyond all human understanding. It was plain, however, to the Nicene fathers that the debate concerned the essential nature of the Christian religion. They saw in the doctrines of Arius a new invasion of old paganism. If Christ, as he said, was an inferior god, then Christianity recognized two gods; and if two, why not twenty? If the god Christ, why not the god Mithra? Why not the gods of Greece and Rome? Why not the endless æons of the Neoplatonists? Where was the line between Christianity and polytheism? And if polytheism were readmitted into theology, what power could keep it out of morals? The world was still pagan; the Christians were still in minority. The emperor, indeed, was on their side, but the emperor himself was almost as much a pagan as he was a Christian; he had not been baptized; in Rome he was still Pontifex Maximus, the official head of the old religion.

Under these conditions Arius came, a Christian polytheist. He came asking the recognition and approval of the church. The Nicene fathers saw behind him, waiting for the opening of the gates, all that pagan world with which they had contended, against which they had suffered martyrdom, over which they had for the moment triumphed. The pagan world, which had endeavored in vain to conquer the church by violence, was now endeavoring to conquer it by subtlety.

Thus when the creed which Esebius offered was found to be so phrased that the Arians were willing to sing it, the fathers proceeded deliberately to insert into it a word which the Arians would not accept. This they found in the expression homoousios, which we translate by the phrase "of one substance." Jesus Christ, they said, is of one substance with the Father. The word was not contained in Holy Scripture. It had the further disadvantage of having been formally condemned and rejected in the discussion of the heresy of Paul of Samosata (268). But it me the necessities of the occasion. It expressed the mind of the orthodox, and no consistent Arian could pronounce it. The word was therefore written into the Eusebian formula, and the church was thus provided with a creed.

We believe in one God, Father Almighty, Maker of all things visible and invisible. And in one Lord, Jesus Christ, the son of God, begotten of His Father, only-begotten, that is of the substance (ousia) of the Father, God of God, and Light of Light, very God of very God, begotten not made, of one substance (homoousios) with the Father, by whom all things were made, both things in heaven and things on earth, who for us men and for our salvation, came down from heaven and was made flesh, and was made man, suffered, and rose again on the third day, went up into the heavens, and is to come again to judge the quick and the dead. And in the Holy Spirit.

This creed was signed. Arius and those who were loyal to his doctrine were excommunicated. The emperor added the sentence of exile. Several lesser matters were considered and decided. Then the council was adjourned. The bishops returned to their dioceses satisfied that the crisis was over, and that he great question was successfully and definitely settled.