Joseph ben Phinehas (d. ca. 920) was a jahbadh (banker) at the Abbasid court during the reign of al-Muqtadir (r. 908–932), a time of fiscal and political crisis in Baghdad. According to the Abbasid kātib and historian Hilāl al-Ṣābiʾ (d. 1056), the vizier Abū al-Ḥasan ʿAlī b. Muḥammad Ibn al-Furāt (r. 908–924, with interruptions) deposited funds confiscated from individuals the regime had executed not with the caliphal fisc but with Joseph ben Phineas and another Jewish jahbadh, Aaron ben Amram—not the first incident of embezzlement in Ibn al-Furāt’s career. In 918, when…