Judah ben Joseph ben Eleazar ha-Kohen, often referred to simply as “the rav” in letters from the Cairo Geniza, was one of the most respected scholars in Egypt during the second half of the eleventh century. Sometimes confused with a prominent Egyptian merchant of the same name, he arrived in Fustat as early as 1050. It has been conjectured that he had family roots in North Africa and studied with Nissim ben Jacob ibn Shāhīn in Qayrawan. In his new home he became a highly regarded teacher and the spiritual leader of the circle of North African merchants around Nahray ben Nissim. Labraṭ ben Moses …