The Semak

Rabbi Yitzchak of Corbeil (c. 1230–1280) was a French Tosafist and legal codifier active in the Île-de-France region. He is best known as the author of the Sefer Mitzvot Katan (The Small Book of Commandments), a systematic enumeration and exposition of the 613 commandments organized by Torah portion, which became influential in medieval Jewish practice and study. Writing in the tradition of the Tosafists, Yitzchak synthesized Talmudic discussions with practical halakha, making Jewish law accessible to scholars and students. His work demonstrates the characteristic French Jewish approach to legal reasoning and represents an important bridge between the Talmudic sources and later codifiers such as the Shulchan Aruch.