In 1561, the Dutch physician Levinus Lemnius published an account of ailments and disorders of the human body. He devoted one chapter to mental illnesses, including the notorious ‘glass delusion’: a form of madness where the patient believed their body, or parts thereof, to be made of glass.

According to Lemnius, one of his patients believed:

“..his buttocks were made of glass, in so much as he darest not do anything [not] standing, for fear that if he should sit, he should break his rump and the glass might fly into pieces… This included the business of sitting down in privies for to relieve himself, the commission of which caused him great peril…”

The highest profile sufferer was French king Charles VI (reigned 1380-1422), who had intermittent episodes where he believed his entire body to be composed of glass.

Source: Dr Levinus Lemnius, De Habitu et Constitutione Corpori, 1561. Content on this page is © Alpha History 2019-23. Content may not be republished without our express permission. For more information please refer to our Terms of Use or contact Alpha History.