LEON, ISAAC DE

LEON, ISAAC DE (d. 1486 or 1490), Spanish rabbi and kabbalist. Isaac was born in Leon in the second decade of the 15th century. He was a pupil of isaac canpanton and was friendly with isaac aboab . abraham b. samuel zacuto in the Sefer Yuḥasin (ed. by H. Filipowski (1857), 226) states that Isaac was "experienced in miracles." He was rabbi of Ocaña. Among Isaac's many pupils were samuel ibn sid , who summarized in his Kelalei Shemu'el many of the traditions and methods of learning in Spain received from his master; Isaac Giacon, the teacher of the well-known kabbalist abraham b. eliezer ha-levi ; Abraham b. Bolat; and Abraham b. Hassan of Salonika. Isaac de Leon became embroiled with don abraham senior and scornfully termed him sone or ("hater of the light") because of heresies which he found in him even before his apostasy. In 1482 De Leon visited Saragossa and became friendly with the Jewish royal courtier, Alfonso de la Caballeria. There he became involved in a violent controversy with the local rabbi Isaac Ziyyat, with reference to the permissibility of certain animal fat, which caused a storm among the Jews of Aragon. A ruling by De Leon on the laws of adjoining owners is   extant (in Sheva Einayim, ed. by J. London, Leghorn, 1745), with which Isaac Ziyyat disagreed. Some of his rulings are mentioned by joseph caro in his Beit Yosef. He wrote a supercommentary to Rashi's Pentateuch commentary. Toward the end of his life he moved to Toledo, where he died. -BIBLIOGRAPHY: A. Marx, Studies in Jewish History and Booklore (1944), 90–92, 432; G. Scholem, in: KS, 2 (1925/26), 270; I. Ta-Shema, in: KS, 45 (1969/70), 124–5; Baer, Spain, index, s.v. Isaac de Leon. (Abraham David)