Menachem Mendel Schneersohn (Third Lubavitcher Rebbe)

Menachem Mendel Schneersohn was the third rebbe of Chabad Chasidut (not to be confused with the later rebbe of the same name). He was raised by his grandfather, Rabbi Shneur Zalman, the first rebbe, and succeeded his uncle, Rabbi Dov Baer, the second rebbe. A recognized authority on Jewish law, his responsa were published in the influential work by whose name he is also known, Tzemach Tzedek. He improved relations with leaders of the Mitnagdim (opponents of Chasidut) through their shared opposition to the Haskalah (Jewish Enlightenment), and played a large role in expanding the reach of Chabad.