The papal bull of 1484 gave monks Sprenger and Kramer full Papal authority to carry out the Inquisition. Soon after their return from Rome they set about compiling a handbook - an exposition of witchcraft and a code of procedure for the detection and punishment of witches. Completed in 1486, it was called the Malleus Maleficarum, or the "Hammer of Witches". It inspired dozens more books with similar tones and themes. This was the torturer's handbook for over 250 years.