A group of fourteen surgeons and geneticists have confirmed that the distinctive Habsburg chin in the Spanish Royal Family resulted from their inbreeding.
The Habsburg dynasty dates back to the eleventh century when the Counts of Habsburg ruled areas of present-day Switzerland. Through successive generations of advancement and intermarriage with different royal families, branches of the Habsburg family sat on the thrones of Austria, Hungary, Croatia, and Bohemia for several centuries. At various points, they also sat on the Spanish and Portuguese thrones, as well.
The Habsburg family maintained their control over several kingdoms and duchies with a very specific strategy – intergenerational marriages. The Habsburgs held the Spanish throne from 1516 to 1700, and throughout this period, nearly 80% of marriages in the Spanish Royal Family were consanguineous.
A consanguineous marriage is between blood relatives deemed too close to marry. In the case of the Habsburgs, these were typically marriages between first cousins, double-first cousins, and not infrequently between uncle and niece. The Catholic Church would have given dispensations to allow the marriages to proceed.
The religious issue of consanguineous marriage is not the only problem. These marriages, and their resulting offspring, have serious medical implications.
Spanish geneticists and surgeons have analysed over 60 Habsburg portraits, as well as written sources, to determine if inter-familial marriage did play a role.
In a paper published in The Annals of Human Biology, they confirmed that the practice of marrying within the family had biological consequences for the Spanish Habsburgs, noting that “the disfigurement worsen[ed], the closer the kinship between the parents.”
Generations of Spanish royals are seen to have strong underbites and facial deformities in their portraits. King Charles II of Spain, the last Habsburg ruler in Spain, suffered from extreme facial deformities and cognitive delays. His lower jaw protruded so far past the upper that chewing was incredibly difficult, and paired with a large tongue, he was unable to speak properly. Suffering from severe cognitive delays, several different people effectively ruled for Charles.
