Menachem Mendel of Kotzk

Menachem Mendel of Kotzk, also known as the Kotzker rebbe (1787-1859) was an Ultra Othodox rabbi and Talmudist and a leader of the Hasidic movement. He was known for his mass Talmudic and Kabbalistic knowledge. It is thought that due to his genius he became very lonely. This led him to leave in seclusion for the last twenty years of his life. He is considered to be the spiritual founder upon which the Ger Dynasty in Poland is based through the teachings of its founder Rabbi Yitzchak Meir Alter (1798(?) - March 10 1866).