'All superstitious arts of this sort, therefore, whether foolish or harmful, constituted through a certain pestiferous association of human beings and demons, as if by a pact of faithless and deceitful friendship, must be utterly repudiated and shunned by a Christian." So proclaimed Saint Augustine in the second book of his De doctrina Christimui, written around 396. 1 And so it remained for the next millennium and beyond. The great Bishop of Hippo was not the first Christian authority to associate superstitious and magical practices with demons, but he was surely the most influential, at least for the Latin West throughout the medieval and early modern periods. His discussions of demonic power and his statements about the inevitable entanglement of any human who sought to invoke or control that power with diabolical evil "as if by a pact" provided a solid foundation for most subsequent learned discourse on diabolic magic. 2 Two centuries later, the encyclopedic Isidore of Seville recapitulated Augustine almost exactly when he declared that "in all these things [magical practices] is the art of demons, arising from a certain pestiferous association of human beings and evil angels." 3 Amidst a bewildering variety of actual practices, what defined magic at a theoretical level for most Christian authorities, and what epitomized its evil, was a perceived unholy alliance between human sorcerers and the forces of hell.·1