Shiism as described by historians
Study the annals of history reveals that the term shia, both during the Prophet’s (PBUH) life and after that, was used to denote the followers of Imam Ali (AS). Some examples of this usage follow. Masudi (d. 345/956), describing events after the Prophet (PBUH), writes: ‘When people’s vows of allegiance (Bayʿa) to Abu Bakr were completed, Ali (AS) and a number of his Shia withdrew to his home’ (121).
Nawbakhti (d. 313/925) similarly notes that ‘the Shias were followers of Ali ibn Abi Talib (AS) who were known by this name during the Prophet’s (PBUH) life and after. Everybody described the Shia as people who ignored other leaders and would only listen to Ali (AS) (15). Abu Al-Hassan Ashari says: ‘The reason why they were called Shia was that they followed Ali (AS) and preferred him over other Prophet’s (PBUH) Companions’ (1/65). According to Shahristani: ‘Shia refers to those who followed Ali (AS) exclusively and admitted his Imamate and succession because of the Prophet’s (PBUH) words about him’ (1/131).
Ibn Hazm argues that ‘whoever believes that Ali (AS) is the best Muslim after the Prophet (PBUH) and the best candidate for leading Muslims and that his descendants are also the best leaders of Muslims is called a Shia. Shia may disagree over other matters, but not on this, and if anyone rejects this fundamental belief, they will not be called Shia (2/113). As all these statements show, there was a group of people who were called Shia by the Prophet both in his days and later. People simply followed the model of the Prophet (PBUH) in calling them Shia.
In light of the above, the defining characteristic of Shiism is following Ali (AS) after the Prophet (PBUH) in terms of religious and political leadership. With all the Prophet’s words regarding Shia and the Ahadith that demonstrate that the Shia had their origin in the Prophet’s own days, there is no need to contrive baseless theories to account for their existence.
We may need to look for the origins of some Islamic sects, such as Sunnism, which was the fruit of following the Caliphs, or such as Mutazilism and Asharism, which resulted from theological debates in the 2nd/8th and 3rd/9th centuries. Unlike these sects, Shiism was not a new thing that appeared after the Prophet’s(PBUH) death as a result of theological conflicts, such as to require an investigation into its origins. Shiism is different from the other sects and is nothing other than the original Islam that was introduced by the Prophet (PBUH), plus the fact that after him, his Household is the only authority to follow and obey.
As Muhammad Kurd Ali writes in Khutat Al-Sham: ‘there were some Companions of the Prophet (PBUH) who were well-known for their close friendship with Ali (AS) in the Prophet’s (PBUH) lifetime, such as Salman Al-Farsi, Abu Dharr Al-Ghifari, Ammar ibn Yasir, Hudhayfa ibn Yaman, Khuzayma ibn Thabit (also known as Dhu Al-Shahadatayn), Abu Ayyub Al-Ansari, Khalid ibn Said and Qays ibn Said ibn Ubada. He quotes Salman Al-Farsi as saying: ‘We took the pledge of allegiance to Muhammad for two reasons: the good of the Muslims and following Ali (AS).’
Also Abu Said Al-Khudri says, again according to Kurd Ali: ‘the Prophet (PBUH) ordered the people to take care of five obligations. They took four and left the fifth. The four things that they took care of were prayer, akat, fasting and Hajj, and the fifth, which they ignored, was the Wilaya of Ali ibn Abi Talib (AS).’ Upon asking whether the Wilaya of Ali (AS) was truly an obligation, Khudri replied that it was as obligatory as the other four (Kurd Ali, 5/251).
Source: Shīa Islam: History and Doctrines, Ayatullāh Jaʿfar Subḥānī, Chapter
