It's known the ruling families of the world are of the same bloodline. This is by design, with the furtherance of domination along with the accompanying social engineering.
If that's hard for you to swallow you have a whole lot of research to do. Do it, it's well worth it.
This planned Conspiracy against humanity has been in effect for millenia, and was ramped up in the 1700's by a coagulating group who are referred to as the Illuminati. Their usage of so-called royalty has been generational.