Shneur Zalman of Liadi (Hebrew: שניאור זלמן מליאדי‎), also known as the Baal HaTanya, (September 4, 1745 – December 15, 1812 O.S.), was an Orthodox Rabbi, and the founder and first Rebbe of Chabad, a branch of Hasidic Judaism, then based in Liadi, Imperial Russia. He was the author of many works, and is best known for Shulchan Aruch HaRav, Tanya and his Siddur Torah Or compiled according to the Nusach Ari. He is also known as Shneur Zalman Baruchovitch, RaZaSh, Baal HaTanya vehaShulchan Aruch, the Alter Rebbe ("Old Rebbe" in Yiddish), Admor HaZaken ("Old Rebbe" in Hebrew), Rabbeinu HaZokein, Rabbeinu HaGodol, the GRaZ.