[Tuco Ramirez]

The areas outside the vicinity of Constantinople were held by Turks.

I'll guess you're either Greek (by ethnicity) or Orthodox (by faith); in any case, if Byzantium was such a bulwark for the Roman Empire, why couldn't they save Rome (as good Romans would). Also, why did they have competing emperors in the West and East?

When Muslims invaded Spain, there was no "Crusades" from the East to help push them back across the Straits. The East made various deals with Islam to prevent an earlier (an inevitable) collapse, while the West fought a death struggle against them (Charles Martel in France, the later "Reconquista" in Spain, etc.).

[Destro]

Constantinople resisted Islam for 1,000 years. The Turks did not appear in Thrace until the end. You are indeed ignorant.