The third antagonist of the Christian faith was rivalry.

The old religion of the Roman world was losing its mastery over human life because of its failure to meet certain imperative needs. It took little account of sin, except such ritual offenses as prevented the proper offering of the sacrifices. It was therefore unconcerned as to salvation. And it dealt in a very vague and uncertain way with the life to come. It was as prosaic, as practical, and as secular as politics; with which, indeed, it was so connected that political position carried religious duty with it, and whoever became a magistrate became a priest at the same time, during his term of office.

But the Roman world was dissatisfied with a religion which lacked the element of redemption. It was a part of the initial advantage of Christianity that it came as a religion of salvation from sin, and brought a definite promise of eternal life. This advantage, however, it shared with two other religions which vigorously competed with it. One of these was Mithraism, a revival of paganism; the other was Neoplatonism, a revival of philosophy.

Mithraism was already ancient in the East before it appeared in the West. Mithra, in the Vedas, was the god of light, both in the sky and in the soul, the enemy of darkness and of error. In the Avesta, he was between the good god Ormazd and the bad god Ahriman. His function was to destroy evil; he was the god of the harvest, and of victory in battle, and of the triumph of the life of man over the death of the body. All the Persians worshipped him. About the second century before Christ the Greeks of Asia Minor identified him with the Sun, and a Pergamene artist made the bas-relief which ever after served as the altar-piece of all the Mithraic shrines. Mithra, represented as a youth with Phrygian cap, and cloak blown by the wind, is slaying a sacred bull. On one side a figure with torch inverted symbolizes night, or winter, or death; on the other side a figure with torch uplifted symbolizes dawn, or spring, or life. The blood of the bull fertilizes the earth, out of which flowers and wheat are rising. Lesser reliefs along the frame show Mithra born among the rocks and adored by shepherds, and after his conquest with the bull feasting with the Sun.

The religion of Mithra admitted the worshipper to the salvation which the god had wrought. There was a baptism in the blood of a bull (taurobolium)  which effected a new birth, concerning which was used the phrase in æternum renatus. There was a stated gradation of spiritual progress, an attaining of now this rank and then that, with accompanying ceremonies. For those who gained the higher privileges there was a sacrament of bread and mingled wine and water. Before the mystic bas-relief, in which the laying of the bull took the place which was occupied in Christian churches by the death upon the cross, was an altar with many lights, before which vested priests sang litanies to the sound of music. The coincidences scandalized and dismayed the Christians.

This religion, entering the Roman world in the first century with the Cilician pirates who were captured by Pompey, was carried by foreign merchants along all the lines of trade, and by foreign soldiers who served in the Roman legions along all the military roads. It appealed to traders because Mithra was a god of prosperity, and to soldiers because Mithra was a god of victory; but it appealed also to thousands of plain citizens because, in the midst of a wicked world, it was a religion of righteousness, hating falsehood and iniquity, and in the midst of sorrow it promised a blessed life to come. Mithra was to descend from heaven and take with him all the faithful into joy everlasting. It made a further appeal to thoughtful and conservative people, because it proposed to include under Mithra, god of the Sun, all the other gods with all their ancient rituals.

It was this hospitality which brought about the eventual failure of Mithraism. The religion grew till it seemed about to conquer its Christian rival. The emperors liked it because with its central deity it lent itself to centralized government. But it was perceived at last that all the old religions, outworn and immoral, were returning in its train. It had had from the beginning two defects which must finally destroy it: it was a man's religion, having no place in it for women; and it was founded on faith in a god who never actually existed, but was a poetic symbol of the power of nature. Thus it waned, and disappeared late in the fourth century, leaving as a heritage to Christianity the name of Sunday for the day of the week which it agreed with the Christians in keeping holy, and the twenty-fifth of December, which it had celebrated as the birthday of the Unconquered Sun.

Neoplatonism was an endeavor to combine the philosophies as Mithraism endeavored to combine the religions. But it was a religion rather than a philosophy because it subordinates knowledge and discredited all intellectual processes, putting its faith in revelation. The current philosophies had long taught men to despise the world of the senses,—except the philosophy of Epicurus, which the Neoplatonists hated. Neoplatonism taught men to despise the world of reason. It offered to uplift its disciples into a new world, a world of revelation, wherein, all things material and even intellectual left behind, they came by trance and ecstasy into the presence of God.

Plotinus wrote the Scriptures of Neoplatonism in his six books called the "Enneads," that is, the Nines. Plato he knew; Aristotle he knew; Oriental religions he may have known, for he lived in Alexandria where the West and the East met. He said that at the heart of the universe is the One, and with the One is thought, and with Thought is the Soul—the world-soul, and the individual soul. The soul lives in the material world. It ought to be the master of the world; but there is matter, source of all evil, in which the soul is imprisoned. How shall it escape? This is the supreme question, beside which all the occupations of the mind of man are insignificant and foolish. Plotinus answered it by saying that the escape of the soul is effected in part by virtuous living, and in part by ascetic practices. Thus living, putting the evil and material world away, meditating in silence upon things divine, the soul enters into communion with God. Porphyry, the chief disciple of Plotinus, said that during the six years of their intimate friendship the master entered four times into this beatific state.

Porphyry, who wrote a book "Against the Christians," hurt his cause by trying, like Mithraism, to save the old religions. The revelation of God, he truly held, is made in all the world; but especially, he added, in the ancient cults with their immemorial liturgies. But the essential weakness of Neoplatonism was in the narrow range of its appeal. It addressed itself to cultivated people, and, among them, to such as had the temperament of the mystic. It was right in its insistence upon a supreme good, beyond sense, beyond reason, beyond reality, but when it endeavored to explain what that supreme good is, the plain man could not understand it.

The emperor Julian tried to substitute Neoplatonism for Christianity, but in vain. The emperor Justinian closed the doors of the Academy of Athens, and the seven philosophers, who alone represented the Neoplatonic faith, took their books and sought the hospitality of the East. Just at that time, however, and anonymous writer bearing the name of Dionysius the Areopagite, whom Paul converted at Athens, appeared at Constantinople and gained immediate acceptance. It was Neoplatonism from beginning to end. It summoned men to renounce the world, to put away from them all hindering conditions, to devote themselves to silence and meditation and solitary absorption in God. It exalted the cloistered life, and for a thousand years determined the monastic mood. It set the note of the mysticism of the saints. Thus Neoplatonism, defeated in its competition with Christianity for the allegiance of the Roman world, nevertheless profoundly affected Christianity itself.

Against Mithraism and Neoplatonism the Christian fathers defended the faith, not so much by controversy as by discriminating sympathy. They hated polytheism and idolatry and all their attendant superstitions and immoralities, and thus far they were the enemies of each of these attempts to save the gods of paganism. But the inclusive purpose of both Mithraism and Neoplatonism found in them a fraternal response. They believed in the Light which lighteth every man, and found gleams of it in all human endeavor after God. Clement and Origen were widely read in Greek literature and philosophy. Clement was a Neoplatonist. Origen was a fellow student with Plotinus in the school of Ammonius Saccas. The perception of God in all honest thought was, indeed, confined mainlyh to the Greek fathers. The Latins were of another mind. Terullian, contemporary with Clement and Origen, hated all philosophy and poetry. This was in part by reason of his temperament, but also, in equal part, by reason of his ignorance. The Latin fathers were unable to read Greek. To Clement and Origen, brought up in Alexandria, the Greek mind and the Greek spirit were gifts of God. They themselves possessed them, being Greeks. And the aspiration after the unseen and ineffable, the endeavor by prayer, and pure living, and continued eager meditation, to ascend to God, was one in which they shared.

The three books which remain of the writings of Clement represent the stages through which the disciple passed in the religion of Mithra, in the religion of the Neoplatonists, in the Eleusinian mysteries—purification, initiation, revelation. Through these stages he was accustomed to lead his pupils in the Catechetical School of Alexandria. Clement's "Address to the Greeks" deals with the error and absurdity of the classic pagan religion, and shows how the greatest of the Greeks had visions of the one God, whom we see truly in the face of Jesus Christ. His "Pedagogue" is a handbook of Christina manners, describing in great detail how a Christian ought to order his life, how he should eat and drink, and furnish his house, and associate with his neighbors. His "Miscellanies" (stromateis  = bags for bedclothes) justify the name, discussing all manner of themes without order or sequence; but the general purpose is to show the character of the true Christian, whom Clement does not hesitate to call the true Gnostic. The progress which Clement endeavored to assist in the life of the individual, he perceived in the religious history of the race. Moses prepared the Jews for Christianity; Plato prepared the Greeks. In all religions, in all good books, by all knowledge, Christ brings men to himself.

The most eminent pupil of Clement, having the same liberal spirit together with greater learning, was his successor, Origen. Origen not only exceeded the fame of his master, but attained a place in the history of theology which is equaled only by Athanasius and Augustine. He had some trouble with ecclesiastical authority, and did not get on well with the bishop, Demetrius of Alexandria. The records do not show that he was seriously at fault. He was so subjected, however, to episcopal interruption of his studies that he removed from Alexandria to Cæsarea , where he suffered martyrdom in the Decian persecution. After his death various vigorous controversies arose as to certain of his teachings. In the course of his voluminous writings he had given his opinion upon almost every possible doctrine, and it was easy to differ from him in detail. There were those who disliked what he said about the preëxistence of souls, or the plurality of worlds, or the resurrection of the flesh. He supplied the theologians for several hundred years with subjects for acrimonious debate. These circumstances hindered and prevented his ecclesiastical recognition. Neither Clement nor Origen was given the honorary degree which is denoted by the title "saint."

Nevertheless, Origen served Christianity in two remarkable and valuable ways: he was the founder of the science of Biblical criticism; he was also the founder of the science of systematic theology.

Origen was the first Christian commentator. He addressed himself through years of laborious study to the perfecting of the text of the Bible, especially of the Old Testament, comparing manuscripts, setting down the Hebrew and the various Greek versions in parallel columns, to make his great work the "Hexapla." And the Bible which he thus studied textually he also studied exegetically. He commented upon it, chapter by chapter. His method here was unfortunate, and delayed for a thousand years the invertigation of the actual meaning of the Bible writers. He made everything into allegory. Thus he occupied himself not in ascertaining what the Bible says, but in reading into it his own ideas. And in this reversal of the true method of study he was followed by of devout readers, who instead of listening to the Bible men, prophets and apostles, insisted upon telling the apostles and prophets what they ought to mean.

Origen was at the same time the first Christian theologian. In his book "Against Celsus," he met as best he could the anti-Christian arguments of that keen antagonist, but in his "First Principles" he made the initial attempt to state in order, with due accompaniment of proof from Scripture and from reason, the doctrine of the Christian faith. From the Gnostics and the Neoplatonists he brought over into the church the idea of a theological system, a synthesis of right belief. He treated of God, one and immutable, revealing himself in the Word, begotten of the substance of the Father, co-eternal and co-substantial, yet inferior, being created. The Word, he said, came to redeem man whose soul is contending with his body. The Word, having first sent the prophets, came at last himself, taking human form. Ordinary men He redeems by the sacrifice of the cross, freeing them from bondage to the devil, and thus making it possible for them to work out their salvation from the flesh. Wise men, spiritual men, those whom like Clement he called Gnostics, He redeems by the illumination of their souls.