Well, a lot of kings and their families suffered from hemophilia. It was a pretty unfortunate blood disease which kept the blood from clotting so even minor cuts and scrapes could prove to be deadly due to increased blood loss and exposure to infection. The problem was that the royal families several hundreds of years ago were really into keeping their bloodline and familial ties as pure as possible. This naturally led to inbreeding as daughters were married off back and forth between kingdoms and family trees. This had the unfortunate effect of keeping the genes supporting hemophilia alive in the bloodline among other birth defects. I'm going to grab some coffee but when I get back I'll tell you more about the political system at the time and why all this was necessary from a cultural, social, and religious point of view as well.