هشام بن عبد الملك
About the question of whether Baqir was known by this name, during his life or after that, there is narration in which, the Caliph, Hisham ibn Abd al-Malik, asks Zayd, Baqir's half brother, about his brother al-baqara (the cow) implying al-baqir. Zaid answers Caliph by saying that the prophet Muhammad, called his brother al-baqir (he who splits open knowledge)