Musa al-Kazim

Musa ibn Ja'far al-Kazim (Arabic: مُوسَىٰ ٱبْن جَعْفَر ٱلْكَاظِم, romanized: Mūsā ibn Jaʿfar al-Kāẓim; 745–799) was a descendant of the Islamic prophet Muhammad and the seventh of the Twelve Imams, succeeding his father Ja'far al-Sadiq and preceding his son Ali al-Rida. Born around 745 in Medina, al-Kazim spent the first twenty years of his life under the care and guidance of his father. This period coincided with the power struggle between the Abbasids and the Umayyads. Following Ja'far al-Sadiq's death, a minority of his followers recognized his other son Isma'il ibn Ja'far as the next Imam, separating from the mainstream Shia Islam and forming the Isma'ili sect. However, Musa al-Kazim attracted the largest following, and his followers ultimately became what developed into Twelver Shia Islam, the largest branch. His Imamate spanned the reigns of the Abbasid caliphs al-Mansur, al-Mahdi, al-Hadi, and Harun al-Rashid. Like his predecessors, al-Kazim avoided politics and devoted himself to religious teachings. He was nevertheless tightly restricted by the Abbasid caliphs and spent much of his adult life in their prisons. To counter these harsh restrictions, he established the network of representatives (Wokala) to organize the affairs of his followers across the Islamic word.

The numerous Alid revolts further increased the caliphs' suspicions, and al-Kazim's final imprisonment ended with his death in prison around 799 in Baghdad, for which Harun al-Rashid has been widely regarded as primarily responsible.