I assume the oldest son of the LAST king gets the crown. Maybe mr. 43 was the last son of the king before?

I've actually considered keeping a block and paper by the comp just to keep track of heirs and where they stand in line to the throne. This way I only have to worry about the first in line and I wont be assasinating/framing any potential decent governors...

Off course it would be nice if the game could do that (hint hint)