HT Reddy

England was unified before 1066, but the parallel has struck me before so your point stands.

Well, there could certainly be references to that particular part of mediaeval history (personally, the way the Dance of Dragons war turned out reminds me of the war between the Empress Maud and King Stephen, but I can't remember enough details of either to say why exactly) without being references to that particular work of historical fiction. I guess there are lots of ideas that are going to be though of by two different authors inspired by similar things totally independently.

Don't know if this has been mentioned, but IIRC, the butcher king of Astapor is called Cleon yes? Cleon is used by Asimov as the last strong emperor, but more importantly cleon was a real person in ancient greece who was one of the first politicians to have influence due to commercial wealth rather than noble ancestry.