When the prophet Muhammad died unexpectedly from illness in 632, divisions arose in the community about the question of succession. Some believed that the Prophet had named his cousin and son-in-law Ali ibn Abi Talib as his successor, and Ali's descendants after him. Other believed that Muhammad had not named a successor, nor had he established a method of choosing his successor. These two groups eventually grew into the two main groups of Islam, the Shi'a and the Sunni. Shiites and Sunnis share many of the same religious beliefs. Both follow the Quran and observe the five Pillars of Islam. At its core, the distinction between the two groups lies in their beliefs about the proper succession of community leadership. Sunni Muslims accept the authority of the Prophet's companions, while Shi'i Muslims believe that members of the Prophet's family have the sole legitimate claim to leadership.
|*believe Muhammad named Ali as successor||*Do not believe Muhammad named successor|
|*Muhammad's family has sole claim to legitimate leadership||*the Prophet's companions have authoritative leadership|
|*rely on authoritative teaching of Muhammad's descendants||*rely on consensus (Arabic, ijma) of religions and religious scholars|
The Sunnis are the larger of the two groups, representing about 85 percent of the world's current one billion or more Muslims. The word sunni derives from sunnah, which means "the trodden path." The sunnah is the body of custom and tradition regarding the exemplary behavior of the Prophet Muhammad, drawn mostly from the hadith, the collection of the traditions concerning Muhammad's life, sayings, and actions. Muhammad is considered the very model of Islamic conduct, inspired by God to live wisely in submission to God's will. The sunnah is a primary resource for Sunni Muslims in family law and in the ethical conduct of their lives. In addition, the Sunni rely on the consensus (Arabic, ijma) of legal and religious scholars, as opposed to the authoritative teaching of the descendants of Muhammad, as the Shi'a do. Sunni Islam is thus a tradition that emphasizes the community's role in providing wisdom about right belief and practice guided by the Quran and the sunnah.
Due to the large numbers of adherents, and the geographical and historical reach of Sunni Islam, the tradition necessarily incorporates a wide diversity of theological and legal views, and further diversity based in historical, geographical, and cultural differences. However, there are a number of historical points on which all Sunni Muslims share common ground. One of the most important of these is the rejection of the Shi'a claim that Muhammad chose Ali and his descendants as the sole legitimate heirs of the leadership of the global Muslim community.
The Shi'a is the smaller of the two groups, currently representing about 15 percent of the world's Muslims. At the time of Muhammad's death, they were known as the shi'at Ali, or the partisans of Ali. Ali finally became caliph in 656, but was assassinated in 661. When Ali died, the Shi'a thought that Ali's son, Hasan ibn Ali should become caliph, but Ali's enemy Mu'awiyah became caliph instead. After Hasan died, the Shi'a supported his brother Husayn ibn Ali. Husayn and his family were massacred at Karbala in what is now modern Iraq by an Iraqi governor, a tragedy that became the defining moment for the Shi'a. It plays a critical role in Shi'i identity, ritual, and politics. It also won Muslims to the Shi'a cause, especially Muslims disaffected with the Umayyads, and non-Arab Muslims wanting to free themselves from Arab dominance.