Part of the myth of the royal family (clearly bogus because they Jim and real Royal Family live in Wythenshawe, Manchester) is that they can be traced backwards into English/Scottish history and give some kind of legitimacy to a single concept of Englishness or something.

What is much more interesting is the web of royal families that have inter-married and shared power & wealth across Europe for a very long time.

I suppose the full family tree would be a bit big but what I picture of trans-national greed & corruption it would be. This kind of tree has been done for 10,000 versions of Fairport Convention so who's up for the big picture?