[RightWhale]

Muslims had carved out most of the Byzantine Empire by then and destroyed their dominance

That would have been Turks, who adopted Islam just as the Normans adopted Christianity, by deliberate, conscious, voluntary action.

[WOSG]

Me:Muslims had carved out most of the Byzantine Empire by then and destroyed their dominance --- You: That would have been Turks, who adopted Islam just as the Normans adopted Christianity, by deliberate, conscious, voluntary action.

I was referring to the Saracen invasion that carved out half the byzantine emipre ... see this timeline:

639 -Muslim armies conquer the southern territories of the Byzantine Empire (Syria, the Holy Land, Egypt, and Jordan).

http://www.metmuseum.org/explore/Byzantium/time.html