Moses ben Jacob of Coucy
Rabbi Moses ben Jacob of Coucy was a French Tosafist and authority on Halakha (Jewish law). He lived in the first half of the thirteenth century, and was a descendant of a family of distinguished scholars. He is best known as author of one of the earliest codifications of Halakha, the "Sefer Mitzvot Gadol" (Hebrew: Large Book of the Commandments; abbreviated "SeMaG"). He studied under Judah ben Samuel of Regensburg (Yehudah HeHasid).
"SeMaG" deals with the 365 negative commandments and the 248 positive commandments, separately discussing each of them according to the Talmud and the decisions of the Rabbis. Rabbi Moses' arrangement and presentation are heavily influenced by Maimonides' discussion of the commandments in the Sefer Hamitzvot and by his codification of the Halakha in the Mishneh Torah. However unlike Maimonides, Rabbi Moses presents lengthy discussions of the different interpretations and legal opinions. He also makes extensive use of other codes, and particularly of the commentaries of Rashi and the Tosafot, usually favouring these Ashkenazi traditions over Maimonides. The "SeMaG" also contains much non-legal, moralistic teaching. Commentaries on SeMaG include Tosefe Semag by Elijah Mizrachi (Re'em) and Ammude Shlomo by Solomon Luria (Maharshal).
In 1240 Moses was one of the four rabbis who were required to defend the Talmud, in a public disputation in Paris, and it is likely that the need for a work like the "SeMaG" was driven by the decrees against the Talmud which had been promulgated in France, and had led to the confiscation and burning of all Talmud manuscripts in 1242.