ISAIAH BEN ABBA MARI (also called Astruc de Savoie):
French rabbi of the second half of the fourteenth century; famous for his controversies and for the divisions he caused among the communities of France. Armed with an order from R. Meïr ha-Levi of Vienna, conferring upon him supreme rabbinical authority, he endeavored to bring all the Jews in France within his jurisdiction, and threatened with excommunication those who did not submit to his authority. He compelled a certain R. Simeon to give him his niece in marriage by threatening him with the loss of his position; and he even attacked Johanan ben Mattithiah, grand rabbi of France, the son of the preceding grand rabbi. Relying upon Meïr ha-Levi's order, he attempted to eject Johanan from his office. Johanan, however, although he had been officially recognized by the crown, instead of appealing to the secular authorities, preferred to carry his case before the rabbis of Catalonia, and applied to Ḥasdai Crescas, and to Sheshet and Moses Halawa. All three justified him completely and severely censured Isaiah and the illegal action of Meïr ha-Levi. The result of the dispute is not known, but the expulsion of the Jews from France, which followed soon after, probably put an end to these rivalries.
- Israel Lévi, La Lutte Entre Isaie, Fils d'Abba Mari, et Yohanan, Fils de Matatia, pour le Rabbinat de France. à la Fin du XIVe Siècle, in R. E. J. xxxix. 85 et seq.;
- Gross, Gallia Judaica, pp. 129, 534.