The Most Inbred Royal in History

When people think of the tragic consequences of the Habsburg family's marriage practices, they immediately picture King Charles II of Spain. However, Charles was only the second most inbred royal. Archduchess Maria Antonia of Austria holds the true, bizarre record. Born in 1669 to Emperor Leopold I and Margaret Theresa of Spain (the famous blonde child from Velázquez's Las Meninas), Maria Antonia was the product of generations of relentless genetic looping.

Her family tree didn't branch; it was a tight, twisted wreath. Consider these staggering genetic facts:

• Her father was her mother’s uncle AND her paternal first cousin once removed.
• Her maternal grandparents were also uncle and niece.
• Her inbreeding coefficient was an astonishing 0.3053—statistically higher than if a parent and their own child had reproduced.

A Miserable Match

Miraculously, while her siblings perished in infancy, Maria Antonia survived into adulthood without the severe, noticeable physical deformities that plagued her Spanish relatives. At 16, she was married off to the dashing military commander Maximilian II Emanuel of Bavaria. The marriage was a spectacular disaster. Maximilian was an extroverted thrill-seeker who found his quiet, genetically burdened wife thoroughly boring. After she endured the deaths of her first two newborns, Maximilian abandoned her in Vienna while she was pregnant with their third child, preferring the company of his mistress in Brussels.

The Christmas Eve Tragedy

Ultimately, the immense genetic load carried by Maria Antonia caught up with her. In 1692, shortly after giving birth to a living son, she contracted a streptococcal infection. Her severely compromised immune system couldn't fight off the postpartum sepsis, and she died at 5:30 AM on Christmas Eve at just 23 years old. In a fittingly gothic end, she requested to be buried next to her mother in Vienna's Imperial Crypt. Her eccentric lead sarcophagus stands out even among the bizarre royal tombs—its steeply sloped lid is adorned with a massive, haunting skull and crossbones. Her only surviving son died at age six, extinguishing her line and triggering the catastrophic War of the Spanish Succession.