Samuel ben David was exilarch in Baghdad during the Mongol conquest of 1258. His name appears in the letter of Jacob ben Elijah of Valencia (or of Venice?) to the apostate Pablo Christiani describing the situation of the Jews in Baghdad at the time. In order to raise funds to defend the city against the Mongol forces, the Abbasid caliph al-Mustaʿṣim (r. 1247–1258) imposed an enormous tax on the Jews, allegedly at the behest of Muslims who, according to Jacob, claimed that the head of the yeshiva and the exilarch were extremely wealthy: “the head of the yeshi…