The philosophy developed in Christianity during the age of the Fathers, mainly in the first five centuries. It represents the first meeting of Christian revelation with the pagan thought of antiquity. Christian intellectuals were aware that they were at the crossroads of two very different worlds, not necessarily opposed to each other. Patristic philosophy, therefore, represents the fusion of the best heritage of ancient Hellenism and the faith of Christianity; which itself had inherited much from Judaism. Three principal strains of philosophizing are discernible, of which the first two were heretical: that Christianity and paganism are utterly opposed to each other, as in Tertullian; that paganism and Christianity are totally compatible, as among the Gnostics; and that the wisdom of Christ and of pagan thought can co-operate, but always pagan philosophy is subordinate to Christianity and to be purified by the higher wisdom of revelation. Much of the conflict with heresy in the early patristic age was due to attempts by some Christian thinkers to subordinate their faith to the intellectual theories of the pagan Mediterranean world.