16 Royals Who Suffered From Hereditary Mutations And Defects Caused By Inbreeding

Consanguinity, the act of marrying a biological relative, has been running in the royal families for as long as there have been dynasties. The main idea behind marrying a relative is to ensure genetic purity by producing children within the family bloodline. 

The royal families were unwilling to share the power of their dynasty, exposing themselves to deadly congenital disabilities.

The European royal dynasties are infamous for maintaining human inbreeding. These marriages represented extreme kinship resulting from the matrimonial policy of the dynasty to establish political alliances through marriage. 

Brother-sister and parent-child marriages were common in ancient royal dynasties of the Egyptian pharaohs and the Persian dynasty.

These types of highly close inbreeding suffer from several limitations, such as uncertain pedigrees. Due to proper documentation, some total sibling marriages are still controversial in the most recent Egyptian royal families. 

However, the genealogical records and mortality-fertility data in the European dynasties are much more extensive, providing a valuable framework for human inbreeding researches.

In humans, some studies display the populations with higher rates of inbreeding, leading to lower inbreeding effect on pre-reproductive mortality and eventually elimination of deleterious alleles in different inbred populations. 

This process is likely to cause temporal changes leading to inbreeding depression, primarily detected in the European royal dynasties.

The Habsburg dynasty, known as the House of Austria, which is one of the essential sovereign dynasties of Europe, conducted uncle-niece and first-cousin marriages to establish political alliances through marriage.

It enabled them to contain their heritage in their own hands. This tradition of prolonged consanguineous marriage resulted in breeding defects such as inbreeding depression, which contributed to the extinction of Spanish Habsburg lineage by the end of the 17th century.

Here is a list of 16 royals who had to suffer from hereditary mutations and defects caused by inbreeding are listed below:

What was the most prevalent disease in many royal families following inbreeding?

Queen Victoria supposedly passed down a Hemophilia B throughout the European royal families. This lineage led to the disease being known as “the royal disease.”

Who is the most inherent person in the world?

Charles II, also known as “the bewitched,” is known to be the most inbred royal with an inbreeding coefficient of 25, equivalent to that of the offspring of two siblings. He was known for having an overly large tongue, epilepsy, and other illnesses.

16. The massive, drool-secreting tongue of Charles II of Spain

A painting of Charles II of Spain
A painting of Charles II of Spain

The Habsburgs were considered one of the most powerful families in Europe for hundreds of years. Their bloodline began in the thirteenth century and ruled until the 1900s through Austria, Spain, and the Roman Empire. 

This dynasty followed consanguineous marriages for such a long time that Joanna of Castille, one of Charles’s ancestors, appears in the family tree fourteen times.

Their line, however, suffered from massive inbreeding leading to the fall of the dynasty. This family has an oversized jawline and a large Habsburg jaw tongue, making eating and speaking extremely difficult. It is also known as mandibular prognathism, causing excessive drooling.

Charles II, known as the bewitched, who looked the part especially, was highly inbred. His inbred quotient was higher than if his parents had been siblings. He was severely developmentally delayed, manifesting as not walking until the age of eight, and could only walk with incredible difficulty. 

Additionally, he was impotent, leaving no heir to the throne and ending Habsburg’s rule in Spain.

15. The massive head of Ferdinand I of Austria

A painting of Emperor Ferdinand I of Austria
A painting of Emperor Ferdinand I of Austria

Ferdinand I of Austria, a descendant of Joana of Castile, was born with hydrocephalus. It is the condition where the water on the brain causes pressure on the sensitive tissues leading to brain damage and leading to his head being abnormally large and disproportionate to his body.

Along with this, he also had Habsburg’s jaw and epilepsy. These severely debilitating conditions resulted from both his parents being related to each other several times.

There was no suitable treatment for his condition, making him limited to physical activities so much that he could not pour himself a glass of water, open a door, or climb stairs unaided. 

Some authors, however, claim how Ferdinand I had artistic talents and was interested in the natural sciences and technical innovations. His linguistic gifts are highlighted because he could speak five different languages.

As the firstborn son, Ferdinand I was confirmed as the successor to his father’s throne. He was regarded as the crown prince at the age of twenty-five when he made his first public appearance as his father’s official representative. 

He liked to sit down on the open end of a wastepaper basket and roll around on the floor during his reign. To everyone’s surprise, he held the throne for a full eighteen years, resigning to his nephew Francis Joseph.

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He married Maria Anna of Piedmont-Sardinia from the House of Savoy in 1831, who was his distant relative. Anna Maria accepted her fate with admirable composure, referring to herself as her husband’s nurse. The marriage remained childless.

14. Hemophilia spread by Queen Victoria throughout European royalty

A photo of Queen Victoria
A photo of Queen Victoria

Queen Victoria can be traced down to most European royalty in the 19th and 20th centuries, meaning Victoria’s genes went all over Europe. She married her first cousin, Prince Albert, and all her children were inbred. 

She had hemophilia, a blood-clotting disorder that she passed on to her children and eventually European royalty, making it known as the royal disease.

Hemophilia is caused when both parents have recessive genes. Queen Victoria had a unique subtype- Hemophilia B. It first appeared in her family in Prince Leopold, Duke of Albany, her eighth son who suffered severe hemorrhages throughout his short life. 

He was always kept protected and under surveillance since even a simple cut could lead him to death; however, he still died at the early age of thirty-one due to a minor fall.

A rumor, the “curse of the Coburgs,” was spread, saying a monk who envied the wealth of the bride’s father, Edward Augustus, Duke of Kent, cursed the future generations of Coburgs with the disease. 

However, Hemophilia scientifically originated from a mutation in either the queen or the sperm of her father. It spread throughout the Royal Houses of Europe.

13. Princess Victoria Melita’s royal never-ending headaches

A photo of Princess Victoria Melita
A photo of Princess Victoria Melita

A granddaughter of Queen Victoria, Princess Victoria Melita, was spared of Hemophilia. However, she had the burden of familial headaches through her heredity and interconnected relations throughout Europe.

Queen Victoria wished for her granddaughter, Princess Victoria, to marry her grandson, the Grand Duke of Hesse, who once married, fought continuously, and the Duke was known for infidelity. 

They had a stillborn son, and their daughter died at the age of eight, after which the couple was free to divorce.

12. King George’s blue urine

A portrait of King George III
A portrait of King George III

King George III of England, one to lose the American Revolution, suffered from porphyria. It is a genetic condition causing the urine to turn purplish-blue and bouts of Madness. 

Recently, he is thought to have bipolar disorder caused by the inbreeding within the House of Hanover and was known to talk until foam came out of his mouth and was known as the mad king in history. 

His rich vocabulary quickly diminished, and he wrote long and confusing letters with sentences containing over 400 words.

He lost the American Revolution war due to his unstable state of mind. His treatments included the application of straitjackets and ice baths.

He was also treated with a medicine made from gentian for a skin condition known to turn urine purplish-blue and was diagnosed with porphyria.

The case of acute porphyria is followed by a degenerated nervous system, including symptoms such as hallucinations, delirium, insomnia, anxiety, and porphyria.

The king’s doctor might have worsened this condition by treating him with arsenic, basically poisoning him.

11. The royal temper tantrum of Maria the Mad, Queen of Portugal

A portrait of Maria I Queen of Portugal
A portrait of Maria I Queen of Portugal

Maria I of Portugal, born into a long line of inbreeding, married her uncle. So, their son, Prince Joao, was also her cousin. She was deeply religious up to the point which might be considered manic and used to howl and make animal noises.

Maria went through a string of chain tragedies within three months. Her elder son and only daughter died of smallpox two months apart, followed by the death of her husband and newborn son.

After the death of her confessor, on whom she placed her entire trust and confidence due to stroke, she had raging temper tantrums as she screamed and wailed in her loss.

Later she was diagnosed as insane and went through a series of horrifying treatments such as ice baths, blistering, and administration of laxatives. None of those treatments worked. Hence, the queen could not attend to her royal duties and had to designate a substitute.

10. Joanna of Castile, who slept beside her husband’s corpse

A portrait of Joanna of Castile
A portrait of Joanna of Castile

Joanna of Castile’s story is the most tragic of the many monarchs’ history. Joanna was an intelligent, curious, and moody woman who married Philip the Handsome, the son of the Roman Emperor Maximilian I, who was a product of inbreeding.

She was fond of reading, leading to the mastery of the Castilian, Catalan, and Gallico-Portuguese languages and French and Latin. She excelled in dancing and playing clavichord; however, she was trained to be a good wife as she wasn’t expected to ascend to the throne.

While Joanna was utterly smitten with her husband, Philip loved his wife physically. He continued being disloyal to her, which made her jealous until she was depressed and eventually became a lunatic. 

Her marriage suffered other tragedies where her only son became fatally ill and then died at the age of eighteen and later gave birth to a stillborn.

She also had to face the loss of her sister and her sister’s son, which led her to take her oath as the heiress, taking the title of Princess of Asturias.

The same year, Joanna went through a complete mental breakdown, after which her husband would abandon her repeatedly as a punishment for her erratic and violent behaviors. 

She would cry herself to sleep and throw her body against the wall in misery. After the death of her husband, he lived her life in solitude as her son sent her back to captivity. Joanna wore black in mourning till her end.

9. Hemophilia that destroyed Alexei Romanov’s empire

A young photo of Alexei Romanov
A young photo of Alexei Romanov

Alexia inherited hemophilia from his mother, which typically affects males that she acquired through the line of her maternal grandmother, Queen Victoria of the United Kingdom. 

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At birth, he was initially a healthy baby, but his navel bled for hours as his blood did not clot when they cut his umbilical cord. Emperor Nicholas II and Empress Alexandra, his parents, did not reveal this condition to the family of the Russian public.

This secrecy caused rumors to rise, such as him suffering from tuberculosis and missing a layer of his skin.

His hemophilia was so severe that even minor injuries such as a nosebleed, bruise, or cut were potentially life-threatening. The recurrence of the condition and long-term recoveries interfered with Alexei’s childhood and education. 

In 1907, he fell and hurt his leg, which triggered an internal hemorrhage. Since the doctors could do nothing, Alexandra asked the Princess Anastasia of Montenegro to find Rasputin, who prayed over Alexei. 

Not long after Rasputin left, the swelling in Alexei’s leg went down. However, alcoholism, sexual promiscuity, and dabbling in the occult tainted Rasputin’s character that symbolized everything wrong with the royal family.

As the disorder and discontent grew, the Russian Revolution began in 1917. It is still uncertain if Alexei’s illness was the reason for the Russian Revolution, the fall of Romanovs, and the royal family’s execution. However, it surely did not help.

8. Depressed and anorexic Elizabeth, Empress of Austria

A portrait of Austrian Empress Elizabeth
A portrait of Austrian Empress Elizabeth

The parents of Austria’s Empress, Elizabeth, were cousins, and she married her cousin, Franz Josef. Her clan, the House of Wittelsbach, was infamous for inbreeding and troubling behaviors.

Elizabeth’s beauty was divine and is often compared to Princess Diana today. Sadly, as one of the most common products of inbreeding, she had a mental illness resulting in depression and anorexia. 

She was timid, shy, and melancholy, which her mother-in-law thought to be a royal liability. She ate very little and exercised obsessively for several hours a day as she developed an eating disorder and traveled a lot as it became a way of escape for her.

She suffered the most when her first child died in 1857, followed by her sister, mother, father, and only son’s loss. Her son died of suicide and has suffered from the same mental illness as his mother. 

She wandered around the globe after his death, looking for solace, during which an Italian anarchist murdered her in 1898 in Geneva, Switzerland.

7. King Ludwig II Overthrown by his Madness

A portrait of King Ludwig II
A portrait of King Ludwig II

King Ludwig II of the House of Wittelsbach was known for being entirely out of touch with reality and mentally unstable. His mother noticed his interest in dressing up and having a vivid imagination as a child. 

He was nineteen when his father died as he ascended the Bavarian throne. He was not prepared for high office as he had no political experience. He continued the state policies of his father and retained his ministers.

He was famous for his youth and good looks, but his real interests lay in art, music, and architecture. He kept himself in the dream world he had created by becoming a personal patron of the composer Richard Wagner. 

He had all the comforts of the king without any responsibilities while the government of Bavaria struggled to run the state.

Ludwig did not get married, did not have any known mistresses, and was under immense pressure to produce an heir. Later, his diary, private letters and, personal documents revealed his homosexual desires, which he struggled to suppress to remain faithful to the teachings of the Catholic Church.

6. Cleopatra was Obese

A painting of Cleopatra
A painting of Cleopatra

Cleopatra is remembered as an enchanting seductress and a robust female ruler who wrapped herself inside a rug and had herself smuggled to Julius Caesar. 

Cleopatra was a Ptolemy as her parents were brother and sister, which was a custom of that dynasty for kings to marry their sisters to acquire their power. Cleopatra married her brother to keep her genetic line, continuing the inbreeding resulting in obesity.

Based on the archeologists’ research, Egyptians were overweight with their diet heavily containing beer and bread. Cleopatra had a hooked nose, a round face, and fat hanging under her chin, unlike how the Roman propaganda portrayed her to be.

Archeologists also claim that she had diabetes, balding in front, and extended back hair. She wore black and red nail polish, sporting a goth look for someone past middle age.

5. Princess Nahienaena’s Incest

A painting of Princess Nahienaena
A painting of Princess Nahienaena

In the early 1830s, Christian commissionaires talked King Kamehameha III out of marrying his sister, Princess Nahienaena. They both got married to other people.

However, their love affair continued, and she gave birth to her brother’s child. They developed a romantic relationship from when they were children, and families approved their relationship.

It was encouraged to marry once they attained maturity but came to a halt when Hawaii was in a state of cultural and political transition. Both their maternal grandparents were half-brothers married to half-sisters.

The king announced their marriage as the first act as an empowered king still, somehow the Christian missionaries were able to persuade him not to do so. 

Princess Nahienaena gave birth to a child shortly after she married another man, and King Kamehameha declared that the child would be the next monarch claiming he was the father. 

Shortly after the birth, both the child and Princess Nahienaena died, which became a sobering and maturing moment for the king, making him committed to the business of modernizing his country.

He was married to a low-level aristocrat, and neither of their sons survived to adulthood. Despite his tragedy, the king successfully transitioned his kingdom from an absolute to a constitutional monarchy. 

He was one of the few indigenous monarchs of the 19th century, maintaining the country’s traditions while adopting European modernity.

4. The many wives of King Rama V

A photo of King Rama V, leader of Siam - Thailand
A photo of King Rama V, leader of Siam – Thailand

King Rama V, one of the most outstanding leaders of Siam (Thailand), lived forever in a fictionalized story on British governess Anna Leonowens. 

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Anna came to Siam as a teacher of King Mongkut’s children, among whom Rama V was the oldest son and the heir to their empire. 

He inherited the throne when he was fifteen-year-old in 1868, and being the well-educated young king, he planned on introducing reforms in the country, eventually modernizing the country.

Rama V had ninety-six wives and mistresses who gave him thirty-three sons and forty-four daughters. He married two of his half-sisters, who birthed his children as well. 

Bhumibol Adulyadej, the current King of Thailand and the richest king globally, is the grandson of Rama V and one of his half-sisters.

King Rama V is known for the modernization of Siam, now known as Thailand, and for preventing its colonization by the British. He abolished slavery and built public hospitals and a railway. 

However, despite his achievements, to avoid being looked down upon by the Western leaders, he only introduced one of his wives- Queen Saovabha, to the public, knowing the shame polygamy and incest would bring him.

3. Nero driven to insanity by inbreeding

A white bust of Roman Emperor Nero
A white bust of Roman Emperor Nero

Roman culture can be easily defined by dark traditions, inbreeding, and insanity. Without mentioning one of the worst Roman Emperor Nero‘s names, the epitome of corruption, destruction, and wickedness cannot be spoken about.

He attained power at the age of sixteen, and over the next fourteen years of his reign, he murdered two of his wives, his mother, and his aunt, while marrying two men, creating incest with his mother, and sleeping with a Vestal Virgin

As if all of these actions weren’t enough, he set fire to Rome, played as the city burned, and blamed the Christians to deflect attention from himself.

This image of impulsive and crazy Nero has been preserved in films and TV series such as Quo Vadis and Nero Burning ROM’s computer software.

It was common for the Roman royals to inbreed to keep wealth and prestige within the family and reduce conflicts over who the heir to the throne should be.

Nero was the son of Agrippina and Claudius, a niece and her uncle, who had an inbred pedigree going back generations. Agrippina married him to reinforce her son’s claim to the throne, proving a dangerous thing for the citizens of Rome. 

His mental status was contributed by the lead poisoning and mainly by the inbreeding.

2. King Tut with a cleft palate and an elongated skull

A golden statue of King Tutankhamun
A golden statue of King Tutankhamun
Source: Wikimedia Common

Inbreeding went as far back as ancient Egypt as the Egyptian goddess Isis married her brother, Crisis, to maintain a pure bloodline. This tradition was followed by many pharaohs and King Tutankhamen as well. 

He was a frail and sick child, and the scans of his mummy showed he had a cleft palate, club foot, and an elongated skull along with persistent malaria and the DNA study on his mummy revealed how those traits were the result of high-level incest.

King Tutankhamen probably spent most of his life in pain with a weakened spine with inflammation and a complicated immune system before dying at the age of nineteen. 

His statues depicted an oddly shaped head and a feminine body, including breasts. According to an author of the study from the Institute of Human Genetics at the University of Tubingen, Germany, his face had full and swollen lips and a slim nose. Still, people found no such evidence based on the new studies.

Tut’s tomb consisted of more than a hundred walking sticks because he had a clubbed left foot in which some of the bones in the toes were dying from a degenerative disease, making him walk ordinarily impossible.

His death was said to be caused by inbreeding rather than any acute causes. 

His compromised immunity led him to death as his body was unable to cope with a severely broken and necrosis of his right foot along with his persistent malaria and other infections and health problems.

1. Caligula’s Bloodthirst

Roman Emperor Caligula
Roman Emperor Caligula
Source: Wikimedia Common

Caligula, the nickname given to famous Roman Emperor Gaius Julius Caesar Germanicus, the third son of Germanicus and Agrippina, was based on the miniature versions of military sandals while sitting with his parents on the German frontier. 

This led the soldiers to call him Caligula– little sandal. His mother and elder brothers were captured, and they died terribly for plotting the praetorian monitor Sejanus in his late teens. 

In attempts to rid himself of Sejanus, believing he may be the potential successor, he too was arrested and put to death by the orders of Emperor Tiberius in 31 AD. 

The same year, he was invested as a priest and lived on the island of Capri in the emperor’s lavish residence and was appointed joint heir with the son of Drusus the younger, Tiberius Gemellus.

Caligula was very tall with skinny legs and a thin neck with sunken eyes and temples and a broad forehead. He had light hair with a bald top and a hairy body. 

He is thought to have attempted to kill Tiberius, who later recovered and returned from the dead. This terrified Caligula of the revenge he would have to face. However, Navevius Cordus Sertorious Macro, commander of the praetorians, smothered Tiberius with a cushion, suffocating him to death.


Consanguinity is no new concept in the ancient kingdoms, which was carried to keep the family bloodline pure and the power within their own families. It was prominent even in modern times from ancient Egypt among the European royalties.

This tradition, however, brought more destruction than prosperity by the time it was a generational system. Many royal disasters resulted from inbreeding as it led to a handful of diseases and deformities, including mental instability, depression, Madness, conditions such as hemophilia, and many other physical deformities. 

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