It is standard these days to describe Shi’ah Islam as a splinter group that formed very early in the history of Islam as a result of disagreement over the rightful successor to the Prophet Muhammad. But the student of religion should consider this explanation as part of the sacred history (traditional narrative) of Islam and not as historical fact.
It has been traditionally believed that the first major religious schism in Islam began when Muhammad named as his successor one of his fathers-in-law, in place of his pious nephew, Ali.
It is possible that the first Shi’ah sect began at the death of the Prophet Muhammad, as most Muslims believe, but there is no way to confirm this history.
Most all Muslims, irrespective of their background or country, are taught this tradition from an early age along with the story of the four original, ‘right’ Caliphs, which includes the story of how Ali finally became the leader of Islam after the first three Caliphs before him.
There are no sources outside of the traditional narrative by which you can confirm the stories of how Islam began. Like all origin stories of a religion, it is a matter of sacred tradition and a matter of faith.
When studying the religions of the world it is crucial to recognize the difference between the traditional religious belief (traditional narrative) and a critical, historical approach to the history of the religion. Origins of Religion
Shi’ah and Sunni
We often speak as if there were only one sect of Shi’ah Islam. There are, in fact, many types of Islam, and the honest student of religion should make a sustained effort to learn at least some of the differences between the many kinds of ‘Shi’ite’ religion, and also the struggles and disagreements among the varied Sunni interpretations of Islam.
The diversity of Islamic religion has come to light, as international news has covered the years of conflict in Afghanistan, Pakistan and Iraq.
More recently, the devastating civil war in Syria has forced clarification of the alliances between various sects of Islam, and has introduced the different Shi’ah sects to a broader public discourse, for example the Alawite sect of Shi’ah Islam, the religion of President Assad’s family.
With this, teachers and pundits have indicated historical similarities and differences of the Alawite sect with Imamiyya Islam, the dominant form of Shi’ah Islam in Iran.
There are, indeed, over a dozen different major forms of Shi’ah Islam and most have been, or are still, at odds with one another.
Amid the many different types of Shi’ah Islam there are different traditions concerning the lineage of important families and leaders. These diverse families and dynasties claim a variety of relationships and connections back to holy men and women of the past, and often back to Muhammad himself.
Sunni tradition insists that the correct leader of Islam is raised up by nomination and approved of by the community of the faithful, and insists that this was true of Abu Bakr (Muhammad’s father-in-law) and all the early Caliphs.
But there has been, as with all empires and their leaders, dissension and disapproval of the different Caliphs throughout the history of the Arab Empires.
The history of Islam is complex, with the original Umayyad Caliphate replaced in the eastern empire by the Abbasid Caliphate, but continuing on in Spain and Northwestern Africa for many centuries.
In the Middle Ages, the Fatimid Caliphate – a Caliphate of the Isma’ili Shi’ah sect – was based out of Egypt. Over six centuries there have been several different Islamic Empires in India.
This is just a bit of the history of Islamic Empires; there are several Islamic empires and hundreds of Islamic dynasties. The very last empire, the Turkish Ottoman Caliphate was finally dissolved in 1924.
All dynasties throughout Islamic history were established during times of discord and conquest, civil war, or religious innovation and interpretation.