Who is Isabella, Queen of England from The Iron King and what is their importance?

Queen Isabella, Queen of England and wife to King Edward is the eldest child and only daughter of Philip the Fair of Spain. She was married to a king in an effort to cement relations between the two warring nations, but is deeply unhappy with her new life there. She has one child, Edward the Third, but hopes of any future heirs are slim as it appears that her husband cares little for her affections.

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