Josiah ben Jesse flourished in the first half of the thirteenth century as part of a family of nesi’im centered in Mosul. He had three brothers—Hodiah (probably the Jalāl al-Dawla of several Geniza letters; cf. infra), Hezekiah, and Solomon (= Jedidiah? [see Gil, sec. 259, ad fin.])—and spent some time in Egypt (Ashmun, Bilbays, Fustat, al-Maḥalla, and, perhaps, Alexandria and Damira) as well as in Damascus, where he met the poet Judah al-Ḥarīzī. At least six different “date points” are attested for Josiah, based on dated or datable sources in which he is mentioned.…