A popular book in late medieval Europe was the Picatrix. By the end of the fifteenth century you could find its many manuscript copies in the libraries of London, Paris, Florence, Prague, and Krakow. Other scholars quoted from it extensively. But one could also find those who condemned its writings – “it is a very pointless book,” said one detractor, “full of superstitions, and structured like a ladder toward idolatry.”
The Picatrix is a manual for using magic, often astral magic, or the powers of astrology. The dominant medieval theory of the cosmos was that the planets and stars not only revolved around the Earth, but had special ways they could influence humankind. The planets, which included the Sun and the Moon as well as Mercury, Venus, Mars, Jupiter, and…
