This is very interesting. Are you familiar with the Accursed Kings Books by Maurice Druon? How accurate is this representation of the decline of Rome's influence in Europe? Is it quite accurate, or is there a lot of speculation mixed with fact?
The only thing that came close to the intrigue of ASOIAF was The Accursed Kings series by Maurice Druon. George R. R. Martin called The Accursed Kings "the original game of thrones", citing Druon's novels as an inspiration for his own series A Song of Ice and Fire. Swapped babies/hidden princes/murder/intrigue... but it is all real history. The audiobooks are good and on Audible. The Iron King is the first book. It is only 3.99 in kindle version now and only 9 bucks for the audiobook if you buy the kindle book https://www.amazon.com/Iron-King-Accursed-Kings-Book-ebook/dp/B00B0PFYKK/ref=tmm_kin_swatch_0?_encoding=UTF8&qid=&sr=