Halakhot Gedolot

Simeon Kayyara, also spelled Shimon Kiara (Hebrew: שמעון קיירא), was a Jewish-Babylonian halakist of the first half of the 8th century. Although he lived during the Geonic period, he was never officially appointed as a Gaon, and therefore does not bear the title "Gaon." The early identification of his surname with "Qahirah," the Arabic name of Cairo (founded 980), was shown by J.L. Rapoport (Teshubot ha-Ge'onim, ed. Cassel, p. 12, Berlin, 1848) to be impossible. Neubauer's suggestion (M.J.C. ii, p. viii) of its identification with Qayyar in Mesopotamia is equally untenable.

It is now generally and more correctly assumed that "Kayyara" is derived from a common noun, and, like the Syro-Arabic "qayyar," originally denoted a dealer in pitch or wax. Rabbinic sources often refer to Kayyara as Bahag, an abbreviation of Ba'al Halakhot Gedolot (="author of the Halakhot Gedolot"), after his most important work.

Kayyara's chief work is purported by some to be the Halachot Gedolot (הלכות גדולות) whereas Rabbi Moses ben Jacob of Coucy (known as "the Semag", from the initials of his major work Sefer Mitsvot Gadol) wrote that it was in fact composed by Rav Yehudai Gaon.

Based on anachronistic discrepancies, the Semag's opinion that it was Rav Yehudai Gaon who composed the work Halachoth Gedoloth was thought to be an error. Rabbi David Gans may have been the first to suggest that it was in fact Rav Yehudai Hakohen ben Ahunai gaon of the Sura Academy who is the Gaon whom the Semag intended as the author of the Halachot Gedolot .

As to the time of its composition all the older authorities are silent. Abraham ibn Daud alone has an allusion to this problem, which has caused much perplexity. According to him (Sefer ha-Kabbalah, in M. J. C. i. 63), "Simeon Kayyara wrote his work in the year 741, and after him lived Yehudai Gaon, author of the Halakhot Pesukot, which he compiled from Simeon's Halakhot Gedolot." This statement cannot be relied upon, as Simeon Kayyara in fact lived in the century following Yehudai Gaon; and Halevy is of the opinion that the names were inadvertently switched, though this reading creates as many problems as it solves.

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