Menachem Mendel Schneersohn, Polish rabbi (d. 1866)
Menachem Mendel Schneersohn (September 9, 1789 – March 17, 1866) also known as the Tzemach Tzedek (Hebrew: "Righteous Sprout" or "Righteous Scion") was an Orthodox rebbe, leading 19th-century posek, and the third rebbe (spiritual leader) of the Chabad Lubavitch Hasidic movement.