Forget the Game of Thrones. Make a series of the real-life history of the twelve sons of Tancred de Hautville. Seldom has one generation of one family so impacted history. Victory against overwhelming odds, and betrayal and treachery as normal family life.
Reads like a history book which, under the circumstances, is acceptable. Lots of narrative. Fills the gap between William the Conqueror and the Renaissance. Well conceived and well written.