The Spanish Habsburg family tree

Why did the Habsburgs inbred?

Finding the perfect spouse for someone from the Habsburg family was a difficult task. And this was not not only because of their looks!

Marrying for love was a luxury the Habsburgs couldn't afford. Each union was meticulously planned, a chess move on the grand board of European politics. Their primary objective: to solidify and expand their vast empire. This strategy, however, had a dark side – a reliance on close relatives as spouses.

The limited pool of eligible partners within the Habsburg family tree meant that marriages between uncles and nieces, and first cousins, became disturbingly common. Out of the eleven Habsburg monarchs who ruled Spain, nine ascended the throne through marriages deemed incestuous by modern standards.

 As a mitigating factor, the people of the 16th and 17th centuries were not aware of the threat of inbreeding. As long as the pope gave his blessing to the union, they could not see any obstacles to it. Still, I find it hard to comprehend that it was not weird to marry your daughter off to your brother.

The consequences of this strategy become painfully clear. Successive generations of Habsburg rulers displayed a noticeable decline in physical and mental health. Charles II, the last of the Spanish Habsburg line, embodied the tragic end result. He suffered from numerous health problems, most likely linked to the extensive inbreeding in his family.

Charles' physical ailments were compounded by his infertility, a critical blow to the dynasty's future. The lack of a clear heir plunged Europe into the War of the Spanish Succession, a brutal conflict that ravaged the continent for fourteen long years.