The jewish Sa'adi khalifahate seems to become a great empire. But I guess that there will be soon internal strifes. The first roman conquest of Palestina was favoured by the struggle between Sadducees, Pharisees, Zealots... With the Arabs, I imagine that we can count an other community. A civil war would be for Nicomedia an occasion to reconquer Egypt where the majority of the population is surely still christian. Plus, these christians should feel themselves opressed by the Jews.