The Tradition of Marrying within the Family in European Royalties

Prince Charles and Camilla are likely second cousins. Camilla's great-grandmother, Alice Keppel, was the mistress to Edward VII of England, and together they produced a daughter, Sonia. Camilla, the current wife of Prince Charles, is the granddaughter of Sonia. Charles and Camilla are second cousins once removed, so they are the product of a second-cousin marriage.

The royal family of Spain is a good example of inbreeding. The current King's parents, Juan Carlos and Sophia of Greece, both have issues with inbreeding. On Juan Carlos's side, we see the remnants of hemophilia passed down due to the intermarriage chronicled by Queen Victoria. Juan Carlos's uncles, Alfonso and Gonzalo, both died from a lack of blood clotting believed to have been caused by their mild inbreeding.

The King's mother, Sophia, arguably has one of the worst cases of modern-day inbreeding. Two of her great-grandparents were brother and sister, and what's even worse is the fact that her great-grandparents are also her great-great-grandparents because the German royal family intermarried.

Prince Philip, late Queen Elizabeth's husband, is also a product of royal inbreeding. Prince Philip, like the Queen, is the unfortunate product of intermarriage that wrapped European royal marriages in the 19th century.

To delve into the specifics, Prince Philip's maternal great-grandparents were Queen Victoria of the United Kingdom and Prince Albert of Saxe-Coburg and Gotha. They were first cousins, sharing the same set of grandparents. This close familial relationship highlights the practice of intermarriage within the Victorian era and its impact on subsequent generations.

Additionally, both of Prince Philip's great-grandfathers played roles in perpetuating the pattern of inbreeding. His maternal great-grandfather, King Christian IX of Denmark, was a prominent figure in European royal circles. King Christian's daughter, Princess Alexandra of Denmark, married Queen Victoria's son, Edward VII, further consolidating the interconnections between royal families.

Prince Philip's other great-grandfather was Grand Duke Louis IV of Hesse and by Rhine. He married Queen Victoria's second daughter, Princess Alice, making them Prince Philip's maternal great-grandparents. What makes this connection particularly notable is that Grand Duke Louis IV was the uncle of Prince Philip's paternal great-grandfather, Grand Duke Ludwig III of Hesse and by Rhine. The marriage of Prince Philip's great-grandparents, Princess Alice and Grand Duke Louis IV, effectively made their children both first cousins and second cousins.

The King and Queen of Greece, Constantine II and Anne-Marie of Denmark, are cousins twice over, just like Queen Elizabeth II and Prince Philip. They are both descendants of Queen Victoria and King Christian, the 9th of Denmark. However, unlike the Queen and Prince of England, the King and Queen of Greece are triply related. They share the exact same consanguinity coefficient, which means the exact same amount of inbreeding.

Empress Napoleon, also known as Mary Louise of Austria, was part of an incredibly inbred family. When Napoleon struggled to provide an heir with his first wife, Josephine, he forced Josephine's daughter to marry his brother. This meant that his stepson was also his brother. However, the most inbred member of the Napoleonic family was Napoleon's second wife, Empress Napoleon. Born as Maria Ludovica Leopoldina Franziska Therese Josepha Lucia, Mary Louise hailed from the House of Habsburg, a family known for its extensive history of intermarriage and consanguinity. In the case of Mary Louise, her parents were double first cousins, intensifying the level of shared ancestry within her immediate family.

Alfonso, the Prince of Spain, was the heir to the Spanish throne in the 1920s, during a highly unstable time in Spanish politics. Like Edward VIII of England, Alfonso renounced his rights to the Spanish throne to marry a commoner. Unfortunately, he passed away in 1938 due to a car accident. His hemophilia, a condition that prevents blood clotting, caused him to bleed to death. Inbreeding within the Spanish royal family played a role in the occurrence of recessive genes inherited by Alfonso. As the great-grandchild of Queen Victoria, who carried hemophilia in her family, Alfonso faced increased risk. The Spanish royal family has a history of marrying close relatives, as mentioned before. Ultimately, Alfonso suffered due to the inbreeding of his ancestors and Queen Victoria's ambition to solidify her reputation as the grandmother of Europe.

Archduchess Gizella of Austria, daughter of Emperor Franz Joseph and Empress Elizabeth, is a lesser-known figure in history. She was the neglected daughter of her parents, who were first cousins. The intense strain caused by their inbreeding affected their children's health. For example, their eldest daughter Sophie died in infancy, likely due to the effects of inbreeding. Another child, Rudolf, suffered from genetic abnormalities and chronic depression, eventually taking his own life. Recent studies have shown a common occurrence of depression within the Habsburg dynasty, suggesting a genetic link. Gizella herself became a figurehead for the consequences of Habsburg inbreeding. She was forced to marry her own cousin at the request of her mother, resulting in physical and emotional suffering for her children. Among her four children, all of them shared eight great-grandparents, who, unfortunately, were not genetically diverse. This situation further compounded the issues caused by inbreeding.

Ludwig II, the Mad King of Bavaria, was a beloved cousin of Empress Elizabeth of Austria. He had a strong appreciation for the arts and commissioned the magnificent Neuschwanstein Castle in the 1800s. However, Ludwig suffered from intense feelings of depression, and his inbreeding is believed to be a significant contributing factor to his mental health struggles. Despite his artistic achievements, Ludwig was eventually dethroned, with his counselors claiming he was insane. Modern studies suggest that Ludwig's depression stemmed from intense guilt over his homosexuality. Nevertheless, inbreeding likely played a role in the intensity of his depression. Interestingly, Ludwig's successor was even more mentally unstable than he was.

Queen Liliuokalani of Hawaii, the last reigning monarch of Hawaii, also had a high degree of inbreeding in her ancestry. It is important to note that there is an unfortunate stereotype about Hawaii having rampant inbreeding, which was not necessarily true in the modern period. However, Liliuokalani's family had close blood relationships. Her grandfather, High Chief Kamehameha, was her great-grandfather twice over because both of her grandfathers were brothers.

King Harald V of Norway holds the distinction of being one of the most inbred royals currently alive. His parents were first cousins, which significantly limited the number of unique great-grandparents he had. While most people have eight unique great-grandparents, Harald only has six. His grandmother and grandfather were not only siblings but also first cousins to each other. Further back in his ancestry, his great-grandmother, who appears twice, was the niece of his great-grandfather. This extensive inbreeding within Harald's lineage makes him the most inbred royal of the present time.