This study examines the controversy between Celsus and Origen, between Irenaeus and the Gnostics (with reference to important Naghammadi texts) and between Plotinus and the Gnostics. Substantial points of contact between Platonic philosophy and Christian theology are shown as well as the insurmountable barriers between them. Of particular surprise and tragedy is above all the misunderstanding between Irenaeus and the Gnostics, whose initiatives...