From ancient times people had sought to conjure magic to evade, ameliorate, or surpass the natural limits of their condition through the help of supernatural creatures. They might have offered rituals of propitiation to pagan gods, invoked the spirits of the dead, or supplicated the daimones, who, as we have seen earlier, were spiritual creatures of indifferent (neither good nor evil) complexion. Once Christianity had exerted its hegemonic influence over Europe, however, all these supernatural beings were reconceptualized as demons and the act of magic became the act of summoning and coercing evil angels. We can see this change reflected in the terminology used: the practice of magic had initially been known as “necromancy” because it involved conjuring with the dead (nekros meaning “dead” in Greek). For example, in the Bible Saul consults a woman popularly known as the Witch of Endor74 regarding the likely outcome of a forthcoming battle, and she raises up the spirit of the former ruler Samuel to give his prophecy (1 Sam. 28:3–20). In the course of the Middle Ages, however, the word “necromancia” underwent a subtle change through popular etymology to “nigromancia” meaning “black magic” (from the Latin niger, “black”), as conjuring came to have less to do with the dead and more to do with demons.

The early Church Fathers, as we have seen, were attempting to forge a new Christian orthodoxy out of competing traditions in Jewish belief and various pagan schools of philosophy, and had to redefine the practice of magic in a Christian context. This meant insisting that all magic was demonic in origin, that the practice of it was always morally wrong, and that the demons’ exercise of magic powers and their access to future and hidden knowledge was necessarily limited both by God and by their nature. Augustine in particular dealt with this problem in a number of his texts, including a treatise that he dedicated to the matter, On the Divination of Demons (De divinatione daemonum). Here he pointed out that demons’ knowledge can indeed appear to be superior to that of humans, since they have far finer acuity of perception, can move more swiftly than humans (thus perceiving worldwide events much faster than human communication would allow), and possess the knowledge they have accrued through long experience since the beginning of creation.