Weyer's works include medical and moral works as well as his more famous critiques of magic and witchcraft: • ('On the Illusions of the Demons and on Spells and Poisons'), 1563. • ('The False Kingdom of the Demons'), an appendix to , 1577. • , 1567, translated into German as: • , 1580, ('A book of medical observations on rare, hitherto undescribed diseases') • 1577, (A book on witches together with a treatise on false fasting), translated into German as: • ... 1586 • 1577, ('On the disease of anger'), translated into German as: • 1585 • , 1564 ('On scurvy') • , 1579. 1885 translation printed , Paris France. Two volume set. Weyer criticised the and the
witch hunting by the
Christian and Civil authorities; he is said to have been the first person that used the term
mentally ill or
melancholy to designate those women accused of practicing witchcraft. In a time when
witch trials and executions were just beginning to be common, he sought to derogate the law concerning witchcraft prosecution. He claimed that not only were examples of magic largely incredible but that the crime of witchcraft was literally impossible, so that anyone who confessed to the crime was likely to be suffering some mental disturbance (mainly melancholy, a very flexible category with many different symptoms). Some scholars have said that Weyer intended to mock the concept of the
hellish hierarchy that previous
grimoires had established by writing those two books and entitling his catalogue of demons ('The False Kingdom of the Demons'). Nevertheless, while he defended the idea that the
Devil's power was not as strong as claimed by the orthodox Christian churches in , he defended also the idea that demons did have power and could appear before people who called upon them, creating illusions; but he commonly referred to magicians and not to witches when speaking about people who could create illusions, saying they were heretics who were using the Devil's power to do it, and when speaking on witches, he used the term
mentally ill. Moreover, Weyer did not only write the catalogue of demons , but also gave their description and the conjurations to invoke them in the appropriate hour and in the name of
God and the
Trinity, not to create illusions but to oblige them to do the conjurer's will, as well as advice on how to avoid certain perils and tricks if the demon was reluctant to do what he was commanded or a liar. In addition, he wanted to abolish the prosecution of witches, and when speaking on those who invoke demons (which he called
spirits) he carefully used the word
exorcist. Weyer never denied the existence of the Devil and a huge number of other demons of high and low order. His work was an inspiration for other occultists and demonologists, including an anonymous author who wrote the (The Lesser Key of Solomon). There were many editions of his books (written in
Latin), especially , and several adaptations in English, including Reginald Scot's "Discoverie of Witchcraft" (1584). Weyer's appeal for clemency for those accused of the crime of witchcraft was opposed later in the sixteenth century by the Swiss physician
Thomas Erastus, the French legal theorist
Jean Bodin and King
James VI of Scotland. == Tributes ==