Before we treat of Christian writings themselves it is essential to notice some related lines of thought and groups of writings which either preceded or accompanied the development of Christian thought and literature, and which either influenced even orthodox thought powerfully, or illustrate foreign elements, aberrations, side-currents, and undertows which none the less cannot be disregarded in tracing the main current of Christian belief. We therefore shall successively treat of the literature extant under the name of Enoch, of the works of Philo Judaeus, of the doctrines of the Gnostics, of the Christian _Apocrypha_, of the _Pseudo-Clementines_ and Simon Magus, and of the _Confession_ of Cyprian and some similar stories. We shall then make Origen’s _Reply to Celsus_, in which the conflict of classical and Christian conceptions is well illustrated, our point of departure in an examination of the attitude of the early fathers towards magic and science. Succeeding chapters will treat of the attitude toward magic of other fathers before Augustine, of Christianity and natural science as shown in Basil’s _Hexaemeron_, Epiphanius’ _Panarion_, and the _Physiologus_, and of Augustine himself. A final chapter on the fusion of paganism and Christianity in the fourth and fifth centuries will terminate this second division of our investigation and also serve as a supplement to the preceding division and an introduction to the third book on the early middle ages. Our arrangement is thus in part topical rather than strictly chronological. The dates of many authors and works are too dubious, there is too much of the apocryphal and interpolated, and we have to rely too much upon later writers for the views of earlier ones, to make a strictly or even primarily chronological arrangement either advisable or feasible. CHAPTER XIII THE BOOK OF ENOCH Enoch’s reputation as an astrologer in the middle ages—Date and influence of the literature ascribed to Enoch—Angels governing the universe; stars and angels—The fallen angels teach men magic and other arts—The stars as sinners—Effect of sin upon nature—Celestial phenomena—Mountains and metals—Strange animals. [Sidenote: Enoch’s reputation as an astrologer in the middle ages.]