Royals throughout history are notorious for inbreeding. But the European royal family by far infamously incestuous were the Habsburgs (Hapsburgs).

The royal house ruled Spain from 1506 to 1700 and held the Holy Roman Empire from 1452 until 1806. These two branches of the family vollied brides back and forth like ping pong balls. Cousins married cousins and uncles married nieces. All in the name of keeping wealth and power in the family and keeping their blood blue. They were oblivious to the havoc all this intermarrying was playing on their genetics. The tragic results were numerous family members with mental illness, intellectual disability, vulnerability to diseases, and a famously unusual continence which came to be known as the Hapsburg Jaw.

Just how inbred where the Habsburgs? Short answer, very. Long answer, well, lets get into it!