"Before the end of the thirteenth century, theologians had little interest in demons, but with Thomas Aquinas and his formidable "Treatise on Evil" in 1272, everything changed. In Satan the Heretic, Alain Boureau trains his skeptical eye not on Satan or Satanism, but on the birth of demonology and the sudden belief in the power of demons who inhabited Satan's Court, setting out to understand not why people believed in demons, but why theologians - especially Pope John XXII - became so interested in the subject."--Jacket.