Chugging on through Medieval Foundations of the Western Intellectual Tradition, I came across the following information which I thought might be of interest to some folks out there:
The earliest conflict to emerge and one that split the religious community into two camps that survive to this day was the question of Muhammad's successor. On this subject the Koran states only that the leader of the Muslim community should be the strongest male member of his tribe. In the event, the succession was contested between Umar, father of the prophet's favorite wife, and Ali, husband of his daughter Fatima. Umar won, giving his name to the first dynasty of caliphs. The Alids, or Fatimids, remained unreconciled. The Ummayads regarded them as sectarians, giving them the label Shi'ites, in contrast to the label Sunni, or orthodox, which they applied to themselves. While the issue was initially one of leadership, the Shi'ites later developed a theological rationale for their oppositional stance, both to the Ummayads and later to the Abbasids, and their movement produced a number of doctrinal offshoots and its own schools of legal interpretation.A second purely intra-Islamic debate that escalated with the Muslim's spreading conquests and one related to the issue of succession was the very conception of the religious community. Side by side with the Koranic statement that the caliph should come from Muhammad's tribe, and hence be Arabic, are verses asserting the universality of the message of Islam and the idea that the bond of faith transcends race, tribe, ethnicity and nation. From the first perspective, a leader who is not Arabic is illegitimate. Since non-Arabs ruled the Muslim world after the eleventh century, Sunni proponents of the Arabist position could justify passive obedience to them, at best, so long as they were orthodox Muslims and defenders of the faith. But this raised problems for Shi'ites whose definitions of orthodoxy varied from that norm. From the universalist perspective, the faith required a broad, rather than ethnically based understanding of the religious community. The missionary principle meant that newcomers were welcome, as was leadership from whatever group could best protect and serve the religious community as a whole. [page 137]