Answer:
By the eighth century, the spread of Islam in various parts of the world determined the origin of the division that today makes the difference between Shiites and Sunnis. All of this began in the year 632, when the death of Prophet Muhammad opened the door for a dispute over who might occupy the position of chief political leader of the entire existing Islamic community.
There, Muhammad's son-in-law claimed succession because he was married to Fatima, the prophet's only living daughter at the time, and having two grandchildren as direct descendants of the prophet. However, most Muslims did not agree with this notion that Ali was too young and inexperienced to occupy such a position. It was then that Abu Bakr, the prophet's friend, was eventually chosen as successor by most Muslims.
Following Abu's term as caliph, two other leaders were hailed as supreme chiefs of the Muslims. It was then that in 656, after the assassination of Caliph Uhtman, Ali was able to rule for a brief period. At that time, strong opposition from the Umayyad tribe eventually established the independence of the caliphates of Medina and Damascus. Shortly thereafter, Ali himself was eventually killed by a group of supporters who did not accept his conciliatory stance.
Even with this dissent, Ali's supporters - known as "Shiat Ali" - continued to fight and question the political legitimacy of caliphates who did not submit to the authority of Muhammad's direct descendants.
Known later as "Shiites," they believe that leaders from the Prophet's lineage are leaders approved by Allah and, therefore, would have the ability to make the wisest political decisions.
On the other hand, Sunnis - so-called for adhering to Sunna, Muhammad's biographical book - have a more conciliatory and pragmatic political and religious action. Concerned about issues that go beyond the field of religiosity, Sunnis undertake a more flexible interpretation of sacred texts, thereby establishing greater dialogue with other peoples and adapting their beliefs over time.
