Abu Ja’far Muhamad ibn ‘Ali, known as al-Baqir (‘the splitter-open’, i.e. of knowledge; also said to mean ‘the ample’ in knowledge) was born in 57/676. His mother, Fatima, was a daughter of the second Imam, Hasan. Thus, al-Baqir joined in himself the two lines of descent from Fatima and ‘Ali. He was about thirty-seven years of age when his farther died.

Like his father, Muhammad al-Baqir was politically quiescent and refrained from openly putting forward any claim. As during his father’s time with Ibn al-Hanafiyya, there was a rival claimant for the allegiance of the Shi’is during al-Baqir’s time. This was al-Baqir’s half-brother, Zayd, who avocated a more politically active role for the Imam and was prepared to accommodate to a certain extent the view-point of the majority of Muslims by acknowledging the Caliphates of Abu Bakr and ‘Umar and by accepting their legal practices.

It is reported that the Caliph Hisham summoned al-Baqir and his son Ja’far to Damascus and debated with them concerning the question of whether ‘Ali, the First Imam, possesed knowledge of the unseen (‘ilm al-ghayb). Hisham is said to have been defeated in argument and to have sent al-Baqir home.

Pressed by the rival claim of Zayd, al-Baqir emphasised the doctrine of nass (specific designation of an Imam by the preceding Imam. However, al-Baqir’s supporters and disciples were in a minority compared with those of Zayd and Abu Hashim, the son of Ibn al-Hanafiyya.

Afurther important development during this period, as seen in the Shi’i sources, was the beginning of an independent stance by the Shi’is began to rely only on the guidance of their Imams on these matters and to reject the rulings of ‘Umar and other Traditionists on whom the rest of the Muslim world was becoming dependent.

As with the other Imams, Shi’is claim al-Baqir as a martyr but there is no concurrence as to the manner of his death, some saying he was poisened by Hisham, others that it was Ibrahim ibn Walid who arranged his death. There is also a wide discrepancy regarding the date of death with variations from 114/732 to 126/743. Most sources appear to settle for 117/735 but this would preclude one historian’s account of how al-Baqir warned Zayd against his open revolt which occured in 122/740.