The ‘opponents’ — the Lithuanian rabbinic establishment’s fierce resistance to the Hasidic movement founded by the Baal Shem Tov. Led by the Vilna Gaon (Rabbi Elijah of Vilna, 1720–1797), the greatest Talmudic genius of the era, the Mitnagdim feared that Hasidism’s emphasis on ecstatic prayer, the mediating role of the rebbe, and popular mysticism would displace rigorous Torah study and undermine halakhic authority. They issued bans (cherem) against the Hasidim. The conflict was one of the most intense internal controversies in modern Jewish history. Over time the two movements accommodated each other; today both streams are components of the Haredi (ultra-Orthodox) world. The Mitnagdic tradition lives on most powerfully in the Lithuanian yeshiva world — including Lakewood, NJ, the largest yeshiva outside Israel.