Moses ben Mevorakh, the scion of a distinguished family of physician-courtiers in Egypt, was the eldest son and successor of the nagid Mevorakh ben Saʿadya and of a mother who also came from a courtier family. Born around 1080, Moses succeeded his father as raʾīs al-yahūd (Ar. head of the Jews) around 1112. Before then, he held the title ʿaṭeret ha-sarim (Heb. crown of the officials), possibly indicating that he was the nagid-designate; certainly his father trained him for the office and arranged for his succession well before his death in early Decembe…