Menachem Mendel Schneersohn also known as the Tzemach Tzedek was an Orthodox rabbi, leading 19th-century posek, and the third rebbe of the Chabad Lubavitch Hasidic movement.

Yosef Yitzchak Schneersohn was an Orthodox rabbi and the sixth Rebbe of the Chabad Lubavitch Hasidic movement. He is also known as the Frierdiker Rebbe, the Rebbe RaYYaTz, or the Rebbe Rayatz. After many years of fighting to keep Orthodox Judaism alive from within the Soviet Union, he was forced to leave; he continued to conduct the struggle from Latvia, and then Poland, and eventually the United States, where he spent the last ten years of his life.