How does Abbasid Caliphate represent a change in characteristics of Muslim leadership?

After Muhammad’s death, Muslim armies stormed out of
Arabiaseeking to conquer other lands and thereby expand the dar al-Islam. Within a
century after Muhammad’s death, Muslim armies had conqueredall of the Persian Empire and
a good three-quarters of theChristian world. The new Islamic empire was ruled by
caliphs, or successorsto Muhammad. Muhammad had no son, so the first caliphs were taken
from hisinner circle of followers. The capital of the empire, therefore, remainedat
Medina.All of these early caliphs were victims of assassination brought aboutby intrigue
and fierce rivalry. A dispute arose concerning the nature of the caliphate, particularly
after the elevation of Othman in 644 signaled a shift to the aristocracyof Mecca. Many
argued that only one related by blood to Muhammadcould become caliph. A civil war broke
out between supporters of Ali, a cousin and son-inlawof Muhammad, and those of the
Umayyad family. By 661, the Umayyads had won, yet Ali’s supporters remained andcontinued
to insist on his heirs’ true legitimacy. Those who supported Ali and his heirs were the
Shiites, while thosewho did not were the Sunni. Both sides would remain hostile toeach
other. The Umayyads moved the capital to Damascus, which was more centrally located.
Power in the empire was increasingly based on Arab identity rather than simply Islamic
faith. Arabs often remained separate from local populations and conversions were even
discouraged. Yet conversions occurred nonetheless. Non-Arab Muslims, or mawali,were
actively discriminated against, yet they continued to rise in powerand prominence. The
mawali helped to overthrow the Umayyads, ushering in the new Abbasid caliphate in 750.
The basis of power was once again the Islamic faith. The capital was moved to Baghdad
and the caliphs adopted aPersian/Byzantine style of rulership. Although in theory the
dar al-Islam or umma (community of all Muslims)was one, in reality it split into
competing caliphates and emirates.