aiSee: Inbred Family Tree

The ancestry of King Charles II, the last Habsburg King of Spain.

Charles II was the only surviving son of his Habsburg predecessor, King Philip IV of Spain and his second Queen (and niece), Mariana of Austria, another Habsburg. The prevalent inbreeding in the Habsburg family genealogy, beginning in prior generations, had given many in the family hereditary weaknesses and left the later generations prone to still-births. In Charles II, it resulted in being disfigured, physically disabled, and mentally retarded.

In Spanish history, Charles II is known as El Hechizado (“The Bewitched”) from the popular belief — to which Charles himself subscribed — that his physical and mental disabilities were caused by “sorcery” rather than the much more likely cause: centuries of inbreeding within the Habsburg dynasty, in which first cousin and uncle/niece matches were commonly used to preserve a prosperous family’s hold on its multifarious territories.

Charles’ own immediate pedigree was exceptionally populated with nieces giving birth to children of their uncles. Charles’ mother was niece of Charles’ father, being daughter of Maria Anna of Spain and Emperor Ferdinand III. Thus, Empress Maria Anna was simultaneously Charles’ aunt and grandmother. Charles descended from his great-great-great grandmother, Joanna the Mad, a total of 14 times — twice as a great-great-great grandson, and 12 times further. In the fifth generation, Charles had only 10 ancestors, where 32 would be normal.

Wikipedia

Technical notes

In this graph, each pair of wedding rings depicting a marriage is composed of two edge arrow heads (with the arrowstyle: "circle" and "half circle", respectively) rather than being represented by a single bitmap icon. This approach allows the smaller ring to be always placed on the wife’s side, and the bigger one on the husband’s. If the layout is changed and the nodes swap their positions, the rings automatically swap theirs, too. Achieving the same effect with a static bitmap icon is generally impossible.