Glass Delusion: Why Did People Think They Were Made of Glass?

The glass delusion was a curious phenomenon from the Middle Ages and beyond, in which sufferers believed they were as fragile as glass.

Nov 22, 2024By Erin Wright, MA History and Public History

glass delusion mental illness people

 

The glass delusion was a psychiatric disorder found in written records in both the Middle Ages and Early Modern Ages, in which people believed that they were made of glass. The disorder caused sufferers great distress and the impending fear that they could shatter like real glass, meaning they would not want to be touched or hugged by anyone. In the fictional story The Glass Graduate, (1613), by Spanish writer Miguel de Cervantes, he describes the maladies of a sufferer: “they would break him, that he really and truly was not like other men, that he was all glass from head to toe.”

 

The curious glass delusion started popping up when clear glass became more regularly used throughout normal people’s lives. As a novelty, it fascinated people, which might explain the rise in the strange condition. It is also worth noting that before glass was invented, other human delusions linked with material substances had manifested, for example, some people had once believed they were made of earthenware.

 

Which European Royals Suffered from the Glass Delusion?

charles vi king of france
Charles VI, King of France, wrapped himself in blankets. Source: Getty Images

 

Two famous royals were known to suffer from the glass delusion; King Charles VI of France and Princess Alexandra of Bavaria. Charles VI was crowned the King of France at only 12 years old in 1380, and ruled until 1422 when he died. He now has the nickname ‘Charles the Mad’ because of his mental illness and episodes of psychosis. His episodes varied and started out small, with the king behaving as if he were feverish, and escalated to forgetting who he was or members of his own family. 

 

Pope Pius II recorded Charles VI’s belief that he was made of glass. Like many with the delusion,  Charles thought he could be shattered; it is stated he had a suit with iron ribs to help protect him, and used soft objects like blankets to protect his body where the iron would be difficult to utilize. In his case it is possible his condition was hereditary, as his mom was thought to have mental health issues.

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wine bottle glass delusions
Wine bottle made of glass, probably British, ca. 1760. Source: The Met.

 

In contrast, Princess Alexandra of Bavaria had a different set of psychologic episodes, including her version of the glass delusion. Besides being a royal, she was also a writer, and she was the fifth daughter of Ludwig I of Bavaria. Besides her obsession with wearing white clothes and cleanliness, in her twenties she also believed that she had swallowed a glass piano as a child that could possibly shatter inside of her. 

 

How Were Psychiatric Disorders Treated in the Middle Ages?

Charles VI king france glass delusions
Charles VI, ca. 1411-13. Source: Wikimedia Commons

 

Mental illnesses like the glass delusion were seen in a different light during the Middle Ages. While some people believed that these episodes were the result of sin, a study published by Cambridge University Press found it was often thought to be brought on by an imbalance of the four humors (phlegm, blood, yellow bile, and black bile), an improper diet, alcohol, or outside forces.

 

The first hospital to treat mental illness in Europe (treat in the loosest of terms), was Bethlem Royal Hospital (also notoriously known as “Bedlam”) in 1247. The first United States hospital was opened in 1753 in Philadelphia, Pennsylvania. At the time they opened, and for many years after, these places were not designed to help people in the correct way, and they were rife with horrible conditions and treatment by the staff. They were considered as ‘less’ than so-called ‘normal’ people, and often treated like animals.

 

Before hospitals were created, ordinary people with illnesses like the glass delusion had very few options. Families could opt to take care of them, or they could end up homeless, requiring them to beg for basic needs like food. They could be seen as a menace or burden to society. They were also some of the individuals who were caught up in witch trials. It wasn’t until the 1900s that people who had mental disorders were seen less as “inmates” and more as patients. It would be longer still for better healthcare and understanding to emerge.

 

Are There Any Cases of the Glass Delusion Today?

glass delusion four humors
The four qualities, elements, humors, and temperaments, unknown artist, c. 19th century. Source: The Wellcome Collection

 

According to the BBC, by the 1830s, there were very few cases the glass delusion recorded. This could have been for a variety of reasons, including the advance in medicine and an increased understanding of mental illnesses, even if the treatment of those who suffered them was often poor. However, isolated cases of the disorder have very occasionally appeared in modern and contemporary times. Similar kinds of delusions have changed following technological advancements, with concrete and microchip implantation becoming more prevalent.

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By Erin WrightMA History and Public HistoryErin is a historian who got her MA at Indiana University Indianapolis in History with an emphasis in Public History and a BA at Grand Valley State University dual majoring in History and Writing. Her specialties are women’s history, medical history, and food history. She is the co-founder of History Gals.