Chabad was founded by R. Shneur Zalman of Lyady, a disciple of R. Dov Baer the maggid of Mezhirich and of R. Menahem Mendel of Vitebsk. When R. Menahem Mendel emigrated to Erez Israel (1777), R. Shneur Zalman replaced him as leader of the Hasidim of Belorussia; it was then that he began to formulate his specific doctrine, which he embodied in his work Likkutei Amarim, also known as Tanya (Slavuta, 1796). His thesis develops a systematic theosophical doctrine on the conceptions of G-d and the world and of man and his religious obligations, based on the Kabbalah of R. Isaac Luria in its original form combined with the Hasidism of the Ba'al Shem Tov and especially that of the maggid of Mezhirich. Habad stresses intellectuality, hence its name Hokhmah, Binah, Da'at ("Wisdom, Understanding, Knowledge"), and thus emphasizes Torah study.