Why Political expansion and unification did not come easily to the Arbr tribesman ?

1. Political expansion and unification did not come easily to the Arab tribesmen. With territorial expansion, the unity of the umma became threatened by conflicts over the distribution of resources and offices. The ruling class of the early Islamic state comprised almost entirely the Quraysh of Mecca.
The third caliph, Utman (644-56), also a Quraysh, packed his administration with his own men to secure greater control. This further intensified the Meccan character of the state and the conflict with the other tribesmen.
Opposition in Iraq and Egypt, comibined with opposition in Medina, led to the assassination of Uthman. With Uthman’s death, Ali became the fourth caliph.
2. The rifts among the Muslims deepened after Ali (656-61) fought two wars against those who represented the Meccan arstocracy. Ali’s supporters and enemies later came to form the two main sects of Islam Shias and Sunnis.
3. Ali established himself at Kufa and defeated an army led by Muhammad’s wife, Aisha, in the Battle of the Camel (657). He was, however, not able to suppress the faction led by Muawiya, a kinsman of Uthman and the governor of Syria.
Ali’s second battle, at Siffin (northern Mesopotamia), ended in a truce which spilt his followers into two groups : some remained loyal to him, while others left the camp and came to be known as Kharjis. Soon after, Ali was assassinated by a Kharji in a mosque at Kufa. After his death, his followers paid allegiance to his son, Hussain, and his descendants. Muawiya made himself the next caliph in 661, founding the Umayyad dynasty which lasted till 750.
4. After the civil wars, it appeared as if Arab domination would disintegrate. There were also signs that the tribal conquerors were adopting the sophisticated culture of their subjects. It was under the Umayyads, a prosperous clan of the Quraysh tribe, that a second round of consolidation took place.