This timeline is based on the supposition that the Umayyads didn't focus on the northern African regions. If not in the rich Byzantine Empire core, Greece and Anatolia, taking this as the base. The Umayyads, though a great force to an empire that has faced defeat 40 years before, and despite The Roman empire remnants fight hard it ends up with an utter defeat taking Anatolia and most of Greece, only remaining independent Crete, Cyprus and Byzantine Italy and North Africa (as the war would have been in the Core of the Empire).