An illustration will make my thought clearer. The votaries of Mithra likened the practice of their religion to military service. When the neophyte joined he was compelled to take an oath (_sacramentum_) similar to the one required of recruits in the army, and there is no doubt that an indelible mark was likewise branded on his body with a hot iron. The third degree of the mystical hierarchy was that of "soldier" (_miles_). Thenceforward the initiate belonged to the sacred militia of the invincible god and fought the powers of evil under his orders. All these ideas and institutions are so much in accord with what we know of Mazdean dualism, in which the entire life was conceived as a struggle against the malevolent spirits; they are so inseparable from the history even of Mithraism, which always was a soldiers' religion, that we cannot doubt they belonged to it before its appearance in the Occident. On the other hand, we find similar conceptions in Christianity. The society of the faithful--the term is still in use--is the "Church Militant." During the first centuries the comparison of the church with an army was carried out even in details;[5] the baptism of the neophyte was the oath of fidelity to the flag taken by the recruits. Christ was the "emperor," the commander-in-chief, of his disciples, who formed cohorts triumphing under his command over the demons; the apostates were deserters; the sanctuaries, camps; the pious practices, drills and sentry-duty, and so on. If we consider that the gospel preached peace, that for a long time the Christians felt a repugnance to military service, where their faith was threatened, we are tempted to admit _a priori_ an influence of the belligerent cult of Mithra upon Christian thought. {xx} But this is not the case. The theme of the _militia Christi_ appears in the oldest ecclesiastical authors, in the epistles of St. Clement and even in those of St. Paul. It is impossible to admit an imitation of the Mithraic mysteries then, because at that period they had no importance whatever. But if we extend our researches to the history of that notion, we shall find that, at least under the empire, the mystics of Isis were also regarded as forming sacred cohorts enlisted in the service of the goddess, that previously in the Stoic philosophy human existence was frequently likened to a campaign, and that even the astrologers called the man who submitted to destiny and renounced all revolt a "soldier of fate."[6]