By the beginning of the second century it was evident that in its conflict with pagan polytheism and philosophy Christianity could hope to win the victory only by taking into itself the fundamental elements of that intellectual life and civilization which the Greco-Roman world had been establishing through centuries. Its claim that the gospel was universal, that it solved the deepest mysteries and satisfied the highest human aspirations, inevitably brought it into the arena of contemporaneous life. It not only was obliged to defend itself in terms current in Greek thought, and to carry on a successful polemic against polytheism, but it had to prove that it offered the fullest, indeed the only true satisfaction of that longing for salvation which men felt. From these necessities of attack and defense came the Greek Apologists of the second century, the most important of whom were Aristides, Justin, Tatian, and Athenagoras. Moreover as the Christian communities multiplied, their members were exposed to many influences which tended to injure or destroy the unity and purity of their belief, so that for self-protection Christianity was forced to develop a formal statement of its faith, that is, to create a dogmatic theology. By formal dogma the common doctrine of the church could be maintained comparatively unimpaired and at the same time the faith could be made intelligible and attractive to the learned of the pagan world. But to give philosophic expression to Christianity’s beliefs meant the Hellenization of this religion. The Gnostics—to whom we shall presently return—were perhaps the first to undertake the construction of a Christian theology, but their aberrations were so extreme and violent that the growing church had to rid itself of them so far as possible. The work of building up a dogmatic system was carried on more slowly in the great catechetical school of Alexandria. We have already seen the beginning of both the apologetic and the theological movements in the Pauline and Johannine writings of the New Testament. Let us now consider the work of the Apologists of the second century.