Johann Weyer
| Johann Wier | |
|---|---|
| Engraving of Johann Wier, age 60, from De Lamiis Liber | |
| Born | 1515 | 
| Died | 24 February 1588 (aged 73) | 
| Other names | Jan Wier, Johan Wier, Johannes Wier, Jean Wier, Ioannes Wierus, Piscinarius | 
| Occupation(s) | Physician, general occultist | 
| Employer | Duke of Jülich-Cleves | 
Johannes Wier (Latin: Ioannes Wierus or Piscinarius; 1515 – 24 February 1588) was a Dutch physician who was among the first to publish a thorough treatise against the trials and persecution of people accused of witchcraft. His most influential work is De Praestigiis Daemonum et Incantationibus ac Venificiis ('On the Illusions of the Demons and on Spells and Poisons'; 1563).