Aaron ben Amram—or, as his name is given in Arabic sources, Hārūn ibn ʿImrān—lived in the second half of the ninth century and the first quarter of the tenth. He apparently began his career as a trader, as in one Arabic source he and his partner, Joseph ben Phinehas , are referred to as al-tujjār (the merchants). Eventually he became a jahbadh (banker). In this capacity, with responsibility for administering, remitting, and supplying funds, Aaron, together with the jahbadh Joseph ben Phinehas (Yūsuf ibn Fīnḥās), played a key role in the financial administration of the ʿAbbasid empire.

The b…