The entire movement which we have been considering is instructive, for it illustrates in a striking way the danger which the growing Church ran of being swamped in the confused floods of Hellenic and oriental thought and mysticism. The conflict with such foes as the Gnostics was one of the chief causes which led to the formation of a body of accepted catholic doctrine, for in dogma lay in part the protection of Christianity. Although the Church was able to free itself of most Gnostic heresies, she could not wholly escape their influence, as we shall presently see. * * * * * The heir of both the Gnostics and the Apologists was the catechetical school at Alexandria under the leadership of Clement and Origen (c. 200-231). The early history of this school is unknown, but it became important at the close of the second century. In it both the Greek sciences and the holy Scriptures were studied, so that it was a natural place for the fusion of secular learning and Christian theology. Clement, who was first a pupil, then a teacher in this school, and at last its head for three years (200-203), was the first to attempt an exposition of Christianity with all the aid that heretical speculation and Greek learning alike could give. We possess from his hand three works of systematic edification. The Protrepticus is addressed to converts, and in it he employs arguments similar to those of the Apologists, Justin and Athenagoras; the Paedagogus gives practical directions for the Christian life; and the Stromateis, “Miscellanies,” is intended to present and establish Christianity as the true philosophy, and so to lead the reader to supreme knowledge (γνῶσις), as its full title announces.[356] From this it is at once evident that the Gnostic movements had had their influence on Clement; and indeed, after combatting Gnostic errors frequently, especially in the third book, he devotes a considerable part of his sixth book and the whole of his seventh to a presentation of the true Gnostic.[357] His view as to the service done mankind by the Greek intellect is summed up in the often-quoted words: “Philosophy was a tutor to bring the Greeks, as the law was to bring the Hebrews, to Christ.”[358] But since it was Clement’s great pupil and successor, Origen, who actually founded Christian theology as a philosophy, and who established his views so firmly that although the Church has rejected much in detail, its dogmas still bear the stamp of his system, we shall pass at once to him and endeavor to set forth in summary the most important elements of his doctrine.