The glass delusion was an external manifestation of a psychiatric disorder recorded in Europe in the late Middle Ages (15th to 17th centuries). People feared that they were made of glass “and therefore likely to shatter into pieces”. One famous early sufferer was King Charles VI of France who refused to allow people to touch him, and wore reinforced clothing to protect himself from accidental “shattering”.
Robert Burton’s The Anatomy of Melancholy (1621) touches on the subject in the commentary as one of many related manifestations of the same anxiety: “Fear of devils, death, that they shall be so sick, of some such or such disease, ready to tremble at every object, they shall die themselves forthwith, or that some of their dear friends or near allies are certainly dead; imminent danger, loss, disgrace still torment others, &c.; that they are all glass, and therefore will suffer no man to come near them; that they are all cork, as light as feathers; others as heavy as lead; some are afraid their heads will fall off their shoulders, that they have frogs in their bellies, Etc.”
Miguel de Cervantes based one of his short Exemplary Novels, The Glass Graduate (Spanish: El licenciado Vidriera, 1613) on the delusion of the title subject, an aspiring young lawyer. Thomas Rodaja fell into a grave depression after being bed-ridden for six months after being poisoned with a purportedly aphrodisiac potion. He claimed that, being of glass, his perceptions are clearer than those of men of flesh and demonstrated by offering witty comments. After two years of illness, Rodaja was cured by a monk; no details of the cure are provided except that the monk was allegedly a miracle-maker.
Dutch poet Constantijn Huygens wrote a Costly Folly (1622) centered on a subject who “fears everything that moves in his vicinity... the chair will be the death for him, he trembles at the bed, fearful that one will break his bum, the other smash his head".
French philosopher René Descartes wrote Meditations on First Philosophy (1641), using the glass delusion as an example of an insane person whose perceived knowledge of the world differs from the majority.
In modern times, the glass delusion has disappeared. “Surveys of modern psychiatric institutions have only revealed two specific (uncorroborated) cases of the glass delusion. Foulché-Delbosc reports finding one Glass Man in a Paris asylum, and a woman who thought she was a potsherd was recorded at an asylum in Merenberg.”
In popular culture
The Glass Delusion, an alternative rock duo from Hull, England, take their name from the psychiatric disorder.
- Speak, Gill (October 1990). ""El licenciado Vidriera" and the Glass Men of Early Modern Europe". The Modern Language Review 85 (4): 850–865. doi:10.2307/3732644. JSTOR 3732644.
- "Music for a glass man". BBC, December 5, 2005. 2005.
- Speak, Gill (1990). "An odd kind of melancholy: reflections on the glass delusion in Europe (1440-1680)". History of Psychiatry 2 (2): 191–206. doi:10.1177/0957154X9000100203.
- Speak, "El licenciado...", p.850
- Robert Burton (1621). The Anatomy of Melancholy.
- Burton, Com.1 Sec.3 comment no. 52
- Cervantes (1613). The Glass Graduate (also known as The Glass Licenciate, The Glass Lawyer; Spanish: El licenciado Vidriera).
- René Descartes (1641). Meditations on First Philosophy. ISBN 0-87484-893-8.