Following Muhammad's death in 632 C.E., the early Muslim community was immediately confronted with the question of who would succeed the prophet as the spiritual and political leader of the community. This was an important issue, since Muhammad had no living male heirs, and left no universally agreed upon successor. The terms for the subsequent and long-lasting divisions of the community, along the lines of proper leadership, are Shi'a and Sunni. The former comes from the Arabic phrase "Shi'at Ali," the "Party of Ali," which supported the leadership of Muhammad's cousin and son-in-law. The term Sunni refers to those who did not support Ali's leadership at this crucial juncture, and is also a term derived from an Arabic phrase, "ahl al-sunna wa al-jamaa," the "People of the Prophet's way and Community." While there are subdivisions within each of these two categories, they represent the main sectarian divide among Muslims.
While Sunnism proper would develop legal and theological traditions in subsequent centuries, its origins lie in this original disagreement over who should lead the young Muslim community. It was generally agreed upon that the next leader, or Caliph, should be a member of the prophet's tribe of Quraysh. According to Sunni tradition, an ailing Muhammad designated his longtime companion Abu Bakr as his successor when he asked his friend to lead the community in congregational prayer. Traditionally an indication of leadership, the role of leading prayer is thus interpreted by Sunnis as a gesture signifying Abu Bakr as the proper heir to the prophet's authority.
Following Muhammad's death, a group composed of émigrés from Mecca (the Prophet's birthplace) and of Medinans who supported them (called the Ansar, Arabic for helpers, supporters), gathered at a place called Saqifah and chose Abu Bakr as their new leader, eschewing dynastic succession. This type of consensus, called shura, was rooted in longstanding methods of communal arbitration in the Arabian Peninsula. Later traditions developed, in the wake of this controversial decision, that had the prophet singling Abu Bakr out more explicitly or even naming him in particular, but these are parts of an ongoing dialogue and disagreement with sectarian adversaries who supported other candidates.
Following Abu Bakr's death in 634, he was succeeded by another prominent Companion, Umar ibn al-Khattab. When Umar was murdered in 644, he was succeeded by yet another member of Quraysh, Uthman ibn Affan. It was Uthman's murder, in 656, that entrenched sectarian affiliations for the long term, since his supporters felt that Ali, upon assuming the caliphate, was lax in his pursuit of the criminals. It is important to note at the outset that Sunnis still held Ali in high esteem, as he was related to the prophet and had been an early convert to Islam. His prominence in the community, even to those who did not pledge him their initial loyalty, was and would remain intact. He would even eventually succeed to the caliphate himself. Yet the initial divide over the justice of his having been passed over was sufficient to lay the groundwork for permanent sectarian divides.
These divides were exacerbated and made firm by the conflict and turmoil that continued to plague the Muslim community in its first decades. The First Civil War took place upon the murder of the third Sunni caliph, Uthman. The caliph, of a mixed reputation because of claims of ineffective leadership and nepotism, was besieged in his home and brutally killed. By this time, Ali had succeeded to the caliphate, and Uthman's supporters accused Ali of failing to avenge his slain predecessor.
|"Golden Age" or "Age of Rashidun"|
|Death of Muhammad||632 CE|
|Caliphate of Abu Bakr||632-634 CE|
|Caliphate of Umar ibn al-Khattab||634-644 CE|
|Caliphate of Uthman ibn Affan||644-656 CE|
|Caliphate of Ali Ibn Abi Talib (cousin & son-in-law of Mohammad)||656-661 CE|
|Fitna: first Islamic civil war||656-661 CE|
|Arbitration between Ali and Mu'awiyah||658 CE|
|Death of Ali ibn Abi Talib||661 CE|