Just as an aside for those who might want to clarify the relationships of Richard III and his ancestors...

Here is a program for PC [#5 in the list] called "Simple Family Tree" that allows one to enter their geneology... and as one example offers a file of the "Kings (and other rulers) of Europe". It is a bit overwhelming as a totality, but it is easy to isolate on just one individual and follow those specific connections.

I personally am not qualified to say that they have it all exactly right, but it seems to be pretty complete and accurate... and is completely editable if one wishes to add, delete or add notes to it.

I browse thru it whenever some item is mentioned that confuses me about which Richard, Henry, James....etc., they are referring to.