At first glance, the practical manual by Emperor Frederick II (1194–1250) and the one by the inquisitor Bernard Gui (1261–1331) do not seem to have any specific features in common. Whereas the first treatise, De arte venandi cum avibus (1240s), deals with the art of falconry, the latter work, Practica officii inquisitionis (1323–24), aims to provide useful knowledge for the inquisitor. Each work has been repeatedly acknowledged as an outstanding example in its particular field of knowledge. Little attention, however, has been given to the specific strategies used in the texts to construct and demarcate expertise.
In 1727, fourteen men and women stood trial before the court of Basel for alleged treasure hunting. There was a rumor that some of them had attempted to find hidden treasures by performing nocturnal ceremonies to conjure spirits that could uncover and release the concealed money. Jacob Schaffner, a shoemaker, stated on record that he had obtained his knowledge of how to conjure spirits from a book he had bought from a Saxon some time ago. Said man supposedly received the book from a Venetian. Another man stated that he had come into possession of this book and copied various parts of it with his friends. This is just one of the many stories that can be found in early modern court documents about treasure hunters trying to conjure spirits. Such handbooks became the center of attention at such trials as the authorities were eager to track them down and place them in safe custody.