Jacob ben Reuben
JACOB BEN REUBEN
JACOB BEN REUBEN (12th century), Karaite biblical exegete, probably a native of Constantinople. He traveled to a number of countries to spread Karaism and at the same time tried to collect commentaries, mainly in Arabic, written by his Karaite predecessors. His biblical commentary Sefer ha-Osher is essentially a collection of excerpts from earlier Karaite authors, hence the frequent glosses in Greek and Arabic; some of these writings are otherwise unknown. His knowledge of the *Khazars and Slavs, whom he mentions, probably derives from the writings of his predecessors. Jacob mainly avails himself of the tenth-century Karaite exegete Japheth b. Ali, simply reproducing passages from his Arabic commentary. The polemics against *Saadiah Gaon and Muslim scholars are also taken from the writings of the Karaite *Salmon (Solomon) b. Jeroham. Of the works by Rabbanite authors, Jacob used those of Jonah ibn *Janāḥ and *Dunash ibn Labrat. Only his commentary on the Later Prophets (excepting Isaiah) and Hagiographa (excepting Psalms) titled Mivḥar Yesharim has appeared in print (Eupatoria, 1836) together with Sefer ha-Mivḥar by *Aaron b. Joseph (the Elder).
S. Poznański, Karaite Literary Opponents of Saadiah Gaon (1908), 66–68; Mann, Texts, 2 (1935), 1275, 1415; Z. Ankori, Karaites in Byzantium (1959), index; M. Steinschneider, Catalog… Leiden (1958), 106–7, 391–2; S. Pinsker, Likkutei Kadmoniyyot (1860), 2nd pag., 80–86; A. Harkavy, Zikkaron la-Rishonim…, pt. 1 book 8 (1903), 152–5.
[Isaak Dov Ber Markon]