For the mountain of Zion

Yeshu‘a ben Judah, known in Arabic as Abū ’l-Faraj Furqān ibn Asad, was a member of the eleventh-century Karaite elite in Jerusalem and was active from 1040 to 1060. His writings in exegesis and law were extensive but remain for the most part unpublished. Yeshu‘a’s writings are noted for their engagement with rabbinic literature, signaling a change in Karaite approaches to the rabbis. In theological matters, he followed in the footsteps of his teacher Yūsuf al-Basīr, writing works of Mu‘tazilite kalām (rationalist theology). He composed philosophical and exegetical works as well but is best known for his Book of Prohibited Marriages (Sefer ha-‘arayot), which was translated into Hebrew from Judeo-Arabic shortly after its writing, by the Byzantine Karaite Jacob ben Simeon. In this work, Yeshu‘a relaxed some of the Karaite laws which radically limited options for marriage. He built his ideas on those of his teachers but clarified them in such a way as to enable his rulings to become authoritative for later Karaites.