הרב אור זרוע

Rav Yitzchak ben Moshe of Vienna (c. 4960/1200–c. 5030/1270), known as the Or Zarua after his great halachic work and also called the Riaz, was among the leading chachmei Ashkenaz of the Middle Ages. Likely born in Bohemia, he was drawn by a thirst for Torah to travel to the major yeshivos of Germany and France. He learned under a remarkable array of masters: Rav Yaakov and Rav Yitzchak HaLavan in Bohemia, Rav Yehuda HaChassid in Regensburg, Rav Elazar of Worms, the Baal HaRokeach, Rav Simcha of Speyer, Rav Eliezer ben Yoel HaLevi — the Raavya, author of Avi HaEzri — and, in Paris, Rav Yehuda ben Yitzchak. He counted himself among the Chassidei Ashkenaz.

He served as rosh yeshiva in Wurzburg, where the Maharam of Rothenburg was his talmid, and later held the positions of av beis din and rosh yeshiva in Vienna, the city with which his name is joined. Toward the end of his life, about 1260, he composed the Or Zarua, which he named from the pasuk in Tehillim — ohr zarua latzaddik. Arranged according to the order of the Talmud, it does not merely give the halachic ruling as the Rambam does in the Mishneh Torah, but brings the passage of the Gemara, explains it, and derives the din — so that it serves at once as a code and as a Talmudic commentary, and preserves much of the teaching of the Baalei HaTosafos and Chassidei Ashkenaz.

Because the full work remained in manuscript until the nineteenth century, later poskim knew it chiefly through the Hagahos Ashri and the Mordechai, and from them through the Beis Yosef and the Darchei Moshe; it was first printed in Zhitomir in 5622/1862. His son Rav Chaim Eliezer, the Maharach Or Zarua, prepared an abridgement of it and carried on a wide halachic correspondence of his own.