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René Descartes -

The glass delusion has appeared several times in historic literature. It is mentioned by French philosopher René Descartes in his book ‘Meditations on First Philosophy.’ The book discussed the existence of God and the immortality of the soul.

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‘El licenciado Vidriera’ (1613) -

A short story by the famous Spanish author of ‘Don Quixote’ also deals with the idea. Cervantes wrote ‘El licenciado Vidriera’ ("The Glass Lawyer") in 1613. It tells the story of an intelligent young man who unknowingly ingests a love potion given to him by an admirer. Instead of having the desired effect, it leaves him with the belief that he is made entirely of glass. The man becomes even wiser and draws crowds of people who wish to meet him.

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The first recorded cases -

But the glass delusion is not just the work of fiction and non-fiction. It first appeared in medical records around the 14th century in Europe. Those who suffered from it were almost exclusively aristocrats and royals.

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A glass body -

There were a few different kinds of manifestations of the disease, but the main similarity was that the person believed they were made of glass. In some cases, they believed their entire body was glass.

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Other manifestations -

It was also common for victims to think that only a particular part of their body, such as the hands, feet, heart, or head, was made of glass.

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The glass piano -

Others believed they had turned into a specific glass object like a vase. In one famous case, a princess believed that she had swallowed a full-sized glass piano and was carrying it around inside her.

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Charles VI -

One of the first and best-known cases in history was that of King Charles VI of France. Charles was put on the throne at the age of 11, and many of his advisors were corrupt.

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Charles "the mad" -

Once he came of age and took control, he made many positive changes and became known as Charles “the beloved.” Sadly, however, he would soon come to be known as Charles “the mad.” He began displaying signs of a severe mental illness at a young age.

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The incident in the woods -

In one psychotic episode that occurred during an expedition with his men, he suddenly believed his companions to be enemies and attacked them. He ended up killing four of them.

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Charles' glass delusion -

He is said to have suffered many psychotic episodes during his life, and one common manifestation of his illness was his glass delusion.

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The glass king -

It’s said that he wrapped himself in blankets and refused to move from his bed for fear of shattering. When he did get up, he wore clothes reinforced with iron to protect his fragile “glass” body.

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A family history -

It’s interesting to note that Charles VI’s father is said to have suffered from bouts of psychosis too. Several of his children and grandchildren, such as King Henry VI of England, also displayed signs of mental illness.

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The delusion spreads -

The glass delusion spread to courts all over Europe over the following centuries. A paper written by two prominent 16th-century doctors told the story of a nobleman who believed he was a glass vase. The man was otherwise intelligent, clear-headed, and logical.

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A new medical challenge -

This unnamed royal reportedly spent much of his time lying on a bed of straw to protect himself. His exasperated doctor went for the tough love approach in an attempt to alleviate the condition.

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Extreme measures -

He lit the straw bed on fire and locked the man in his room! The man became desperate to escape and banged violently on the door screaming for help. The doctor released him, and pointed out that if he was made of glass then his hands would have shattered.

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The glass derrieres of the 17th century -

There are several cases in the 17th century of men who believed that their backsides were made of glass. One nobleman named Nicole du Plessis suffered from this delusion and was scared to sit down without a pillow.

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Questionable treatments -

It’s been recorded that his doctor gave him a good thrashing so he would realize that if he felt pain then he must have a normal human behind and not a glass one!

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Princess Alexandra of Bavaria -

Another famous case of a royal suffering from the glass delusion was Princess Alexandra of Bavaria. She was born in 1826, so she was one of the last recorded cases of the illness, which had all but died out by the end of the 19th century.

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Intelligence and mental illness -

Princess Alexandra was similar to King Charles VI in that she was highly intelligent. However, even before the glass delusion began she displayed some strange behaviors.

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Obsessive tendencies -

It’s said that she was obsessed with cleanliness and would only wear white clothes.

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New symptoms -

One day her family noticed she was acting even stranger than usual. Whenever she passed through a doorway she would turn sideways and walk through very carefully.

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The "childhood memory" -

She informed them that she had remembered something very important. The princess claimed that when she was a child, she had swallowed an entire grand piano made of glass. The piano was still inside her, so she had to be very careful not to break it...

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Examining the cause -

The question remains: what caused this strange belief? In the case of King Charles VI, modern psychiatrists believe he displayed clear signs of schizophrenia.

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Vulnerability and anxiety -

The glass delusion seems to be a manifestation of a common anxiety experienced by those in positions of power during the medieval and early modern period. Contemporary psychologists theorize that it was a way of expressing how fragile and exposed they felt.

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Before glass - Historians of psychiatry have also linked the glass delusion to other similar delusions throughout history. Prior to the glass delusion, there was a common illness that caused people to believe they were made of earthenware.

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The Industrial Revolution - After the glass delusion died out, the Industrial Revolution came and some people began to believe they were made of cement. The common factor in each of these cases is a belief that they are made of a material that is relatively new and innovative, but which makes them susceptible to breaking or shattering.

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Contemporary manifestation - Psychiatrists have even suggested that a contemporary version of this delusion is that a microchip or mind-reading device has been planted in the patient's head to monitor their thoughts. This is a common delusion experienced by people with schizophrenia.

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Conclusion -

Luckily, we have much more humane and efficient ways of treating mental illness compared to the Middle Ages. That being said, the human mind is still a vast frontier with plenty left to discover.

Sources: (History) (BBC) (Ancient Origins)

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What next? -

The glass delusion isn't the only strange psychiatric phenomenon recorded in history.

Take a look at some of the most extreme cases of mass hysteria ever to take place.

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