As always there were unintended consequences. Muhammad the Prophet's followers launched their imperialism intending to be an elite caste garrisoned in the conquered areas keeping guard or order and enforcing taxation. It was the policy of the early caliph to disturb the conquered as little as possible, so long as they paid their taxes. There was no interest in converting the conquered to Islam. In the interest of order they left the social and religious order of the conquered intact – social order and religious authority having some connection. But also there were the old landowners, chiefs and headmen, and the conquering Muslims left them with their authority in the villages, subservient, of course, to the conquerors – a method of imperial administrations that was ages old. For the sake of order, the caliphate sent governors to the conquered areas to oversee the collection of taxes and to supervise the distribution of pay to the occupying Arab warrior elite.
Problems with this order of things in the conquered area were developing. It was a question of maintaining an elite through segregation versus integration, with segregation being historically difficult and diffusions common.
But a bigger problem concerning order came within the Muslim community. It was the old problem of succession and more civil war – boring for a reader in its repetition but dramatic for the participants.
Islam's Succession Problem and Civil War
In the late 670s the aging caliph Mu'awiyah nominated as his successor the son of his favorite wife, a Christian. That son was Yazid, and the nomination was confirmed by the consultative body Mu'awiyah had created from leaders of the Arab tribes. Helping Yazid's succession was his having been a heroic figure in the assault against Constantinople, and perhaps also some bribery.
Mu'awiyah died in 680, and a few prominent people were among those who did not accept his son's succession. One...