ʿAbd Allāh ibn Saba’, also called Ibn Sawdā’ (Ar. son of the black woman), was a Jewish convert to Islam during the caliphate of Uthmā̄n (r. 644–656). Classical Sunni sources portray him as a progenitor of Shiʿism. Both Shīʿī and Sunni sources relate that a Yemenite Jew named ʿAbd Allāh ibn Saba’ was the first person to publicly proclaim that Muḥammad was the expected messiah.  After Muḥammad’s death, however, he transferred his allegiance to ʿAlī, announcing that ʿAlī was the messiah who would return (Ar. rajʿa) at the end of time, riding on the clouds. The earliest Shīʿī groups, largely…