This guest post was written by our very own MikeSchilling!
There a meme that surfaces every so often (for instance, in this episode of 30 Rock that European royalty have been damaged by centuries of inbreeding. The best real-life example of this was King Charles II of Spain, who,
was born physically and mentally disabled, and disfigured. Possibly through affliction with mandibular prognathism, he was unable to chew. His tongue was so large that his speech could barely be understood, and he frequently drooled.
Charles belonged to the House of Habsburg, in fact, he was the last Habsburg king of Spain, and a direct descendant of the first such, Charles I of Spain (almost always referred to as Charles V, since he was the fifth Holy Roman Emperor named Charles, the first being Charlemagne.) The Habsburgs had a genius for marrying princesses and inheriting their lands when no direct male heirs were available.
Charles V was the heir of centuries of this:
- He was the King of Spain because his father had married the eldest surviving daughter of Ferdinand and Isabella, whose sons died young. This also made him the ruler of the Spanish empire in the New World. Further, Spain rules Naples, Sicily and Sardinia.
- He was the ruler of Burgundy in France and the Low Countries (more or less the modern Benelux nations) because his grandfather had married the only child of the Duke of Burgundy
- His brother Ferdinand I became king of Bohemia (today’s Czech Republic) and Hungary by marrying their king’s only daughter, who inherited when her only brother died without issue.
- And in addition to all of that were the hereditary Habsburg holdings in what’s now Austria and the title of Holy Roman Emperor (more or less the overlordship of Germany.)
When you consider the amount of territory Charles V ruled, the only comparisons are to people like Alexander and Napoleon. The difference is that they conquered it, while his ancestors married into it. The Habsburgs were not about to have this game played against them, and developed a counter-strategy: to an appalling degree, Habsburgs only married Habsburgs, culminating in poor Charles II. I’d been curious for a while just how far this went, so I built his family tree, going back four generations: just ancestors, no siblings or other spouses, to keep it simple. When a person appear in the tree more than once (as several do), their name is followed by the same letter at each location. Where the fourth-generation ancestors are themselves related, that’s called out.
To summarize, where for most people a tree going back this far would contain thirty-one different people, Charles’s tree contains only twenty-three. Moreover, where normally the sixteen great-great grandparents would all be different people, none of them closely related, here we see only ten people who don’t appear elsewhere in the tree, and only four of whom aren’t closely related. The most egregious example of inbreeding came with Charles’s parents. His mother, Mariana of Austria, was the niece of his father, Philip IV (Philip’s sister’s daughter). Though it’s actually worse than that, because on her father’s side, Marianna was Philip’s first cousin once removed (her father, Ferdinand I, and Philip IV were both grandchildren of Charles II of Austria.) And it’s even worse than that, because his parents’ mutual ancestor Charles II of Austria had also married his own sister’s daughter.
Among Charles II’s afflictions was the inability to father children; on his death, this resulted in a dispute that led to the War of the Spanish Succession, which lasted thirteen years and took hundreds of thousands of lives.