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”.
[One sufferer] was cured of this obsession by a severe thrashing from  the doctor, who told him that his pain emanated from buttocks of  flesh.

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”.

[One sufferer] was cured of this obsession by a severe thrashing from the doctor, who told him that his pain emanated from buttocks of flesh.