De Scypho Vitreo per certum humanae vocis sonum fracto - The Dutch translation

The well-known wine merchant Nicolaes Petter practiced and taught wrestling in the basement of his house. Petter was also known for his ability to break a glass with just the sound of his voice. This phenomenon was first described by Daniel Georg Morhof (1639-1691). Morhof's letter is seen as a very important historical document. It is also popular with practitioners of Renaissance martial arts and other people studying or interested in Nicolaes Petter.