Jacob ibn Jaw lived in Cordova in the second half of the tenth century. He and his brother Joseph became rich in the silk trade and had government contracts that brought them into contact with the country’s rulers. According to our principal source, the Sefer ha-Qabbala (Book of Tradition) of Abraham Ibn Da’ud, the ḥājib (vizier) al-Manṣūr Ibn Abī ʿᾹmir (r. 976–1002) appointed Jacob civil head (Heb. nasi) of the Jews in the Cordovan state, “from Sijilmasa to the river Duero,” with administrative, judicial, and taxation powers, entitlement to public honors, and …