The Gnostics never formed any single community or school, but they comprised groups which exhibited the greatest diversity and range of beliefs and of morals; the most famous and influential individuals were Basilides, who taught at Alexandria in the time of Hadrian, and Valentinus, who was active at Rome in the middle of the second century (c. 140-c. 165). Gnosticism did not originate within Christianity, but rather antedated it. All its forms arose from some combination of oriental religions and mythologies with Greek modes of philosophic thought, which in many ways remind one of later Neoplatonism. When Christianity was taken into the Gnostic systems, it was inevitable that it should be modified, reshaped, and stated in forms which might contain gross error. Yet it would be a mistake to regard the Gnostics as fundamentally foes of Christianity. Even if we cannot go so far as Harnack and call them “the theologians of the first century,” and attribute to them the first place in the early formation of a Christian theology,[348] we must recognize that they did a great, and in some ways a permanent, service to the new faith. They were seekers after a philosophy of history; they interpreted Christianity as the religion which replaced both paganism and Judaism, and they held that the appearance of the redeemer had completed the development of the human race and had consummated the history of the universe. Such a view, which in itself was quite in accord with the views of Christians generally, led the Gnostics to reject the Old Testament because it was supplanted by the new revelation; the Apostolic writings they believed to contain first of all the rule of faith when taken at their face value, and secondly to hold a secret and deeper meaning, which could be obtained only by allegorical, that is, by esoteric interpretation. But thus far the Gnostics and the mass of Christians were still in essential agreement, although the latter held to faith (πίστις) as the basic element in their religion, while the former exalted knowledge (γνῶσις) above it.