Aaron (Ar. Khalaf) ben Joseph ha-Kohen ibn Sarjado was gaon of Pumbedita from around 942 to 960. Ibn Sarjado was not from a family of scholars, but married into a wealthy Jewish banking clan in Baghdad that had come to play an increasingly important role in the selection of geonim and exilarchs. His father-in-law, Bishr ben Aaron, is credited with brokering the settlement that ended the protracted dispute between Saʿadya Gaon and the exilarch David ben Zakkay. Ibn Sarjado’s first official post within the hierarchy of the yeshiva came when Mubashshir, gaon of Pumbedita, appointed him resh k…