If I read that a dozen times, I might come to know all the players. Interesting stuff, though.
The coming of Islam cut off the two halves of Europe just like Islam cut off Europe form Northern Africa/Ethiopia for centuries.
If you are interested there is a three part series of books by an englishman named Norwhich. Byzantium, The Ris, Apogee, and Fall. I have them and have read them several times. Very good reading. The author tells a good story and it does not come across as dry.