Originally Posted by
Linke
that is the process known as the second fitna, or the great Shia-Sunni divergence, wich might be a bit sensitive to some. It occurs after the fourth Rashidun Caliphs, Utmans family, the ummayads have nestleded themselves into powerful positions in the provinces of the former roman east. Then as Ali after Uthmans death finaly is made Caliph, the powerful ummayads assert themselves as their own caliphate (+ a guy ruling Egypt being a bit neutral), furthermore throughout the empire a group know as the Khawarij gain land and control, a group of radical islamic rightists who first take the recent incention of military Jihad (made by Omar to justify his conquests) to mean extermination of all non-muslims, and muslims who don't follow their teachings. Perfect for a civil war campaign, although already the armies were quite changed, also in the Byzantine empire.
As for the treatment of non-arabs I agree, of course in the local Persian tradition they weren't brutalt represed, but largely absent from government, except for example in Tabaristan where the Arabs instead of conquering the local pre-islamic dynasties made them vassals. An interesting note is the dual meaning of thr contemporary (right?) word Mawali, refering both to non-Arab islamc converts, and friends in general, but also subjects, and even slaves