Origin of Shia Islam

Shia Islam originated as a response to questions of Islamic religious leadership which became manifest as early as the death of Muhammad in 632 CE. The issues involved not only whom to appoint as the successor to Muhammad, but also what attributes a true successor should have. Sunnis regarded Caliphs as a temporal leaders, (originally elected by general agreement, though later the hereditary principle became the norm). To the Shiite, however, the question of succession is a matter of designation of an individual (Ali) through divine command. In the same way, Shias believed that each Imam designated the next Imam by the leave of God. So within Shia Islam it makes no difference to the Imam's position whether he is chosen as a Caliph or not.

Historians dispute the origin of Shia Islam, with many Western scholars positing that Shiism began as a political faction rather than as a religious movement. However, Jafri disagrees, considering this concept or religious-political separation as an anachronistic application of a Western concept. Sunnis, on the other hand, often claim that Shiite beliefs only first formed under the scheming of Abdullah ibn Saba'; Sunnis reject the idea that Ali followed any beliefs that were contrary to the rest of the Sahaba.

Shia View

Shia Islam began when Abu Bakr, Umar and Abu Ubaydah al Jarrah offered each other the helpers (ansar) despite the announcement of Ghadir Khumm where Ali was declared master of the believers. Ali and his supporters stayed in his house then Abu Bakr sent Umar to threaten those inside by attempting to burn the house. After a confrontation Ali eventually pledged allegiance to Abu Bakr. Ali would remind the companions of the tradition of Ghadir over 10 years later in the courtyard of the mosque in Kufa in a tradition known as Yawm al Ruhba. Shi’i sources are clear about the collusion of the above individuals as well Sunni ones, for example where Umar announces close to his passing that he would elect Abu Ubaydah or Salim (one of the first people to pledge allegiance to Abu Bakr) if they were still alive. Therefore the Sunni leadership doctrine was really a reaction by some individuals to Ali being announced as their master.

These personalities are known by some as the people of the contract (ahl al-‘Uqd):

It was narrated that Qais bin 'Ubad said:

"While I was in the Masjid in the first row, a man pulled me from behind and moved me aside, and took my place. By Allah, I could not focus on my prayer, then when he left I saw that it was Ubayy bin Ka'b. He said: '0 boy, may Allah protect you from harm. This is what the Prophet instructed us to do, to stand directly behind him.' Then he (Ubayy) turned to face the Qiblah and said: 'Doomed are Ah1 Al-'Uqd, by the Lord of the Ka'bah! - three times.'Then he said: 'By Allah, I am not sad for them, but I am sad for the people whom they have misled.' I said: '0 Abu Ya'qub, what do you mean by Ah1 Al-'Uqd?' He said: 'The rulers."'

https://sunnah.com/nasai/10/32

From then on the different Shia groups developed different Imamate theories with the most popular current form alleging having 12 imams with the last one in occultation, which means he has been hidden from the view of the people until the end of time. Other Shia groups do not limit the number of imams and instead encourage that the imam be a just and knowledgeable leader.