"A great soul has descended to earth. Shney-Or (two lights): he will spread the light of the Torah in both its revealed and mystical aspects."
--Rabbi Israel Baal Shem Tov, regarding Schneur Zalman, the "Alter Rebbe," at the age of 3.

Rabbi Schneur Zalman of Liadi, The Alter Rebbe (1745-1812), was born in Liozna, a town in White Russia. As a boy, he learned with various great scholars, and when he was barely twelve, his teacher informed his father, that he could no longer teach the boy due to his advanced level. At his Bar-Mitzvah, the greatest Torah scholars saw the prodigy in him, and by the time he reached the age of eighteen the Alter Rebbe travelled to Mezritch where he met up with the Maggid. Rabbi Schneur Zalman became a fervent adherent to the Chassidic teachings of the Maggid, and the founder of the Chassidic movement, Rabbi Israel Baal Shem Tov.

The Chassidic movement may have begun before the Alter Rebbe, however, he pioneered the "Chabad" approach. As the movement grew, so did its adversity. The Alter Rebbe was persecuted and then arrested by the Czarist regime in 1798 in Petersburg for his efforts to strengthen the movement and for the dissemination of its teachings. As the Alter Rebbe sat in prison he felt compelled to share the beauty of Torah and the depth that Chassidut had to offer with the Czar's ministers. After being imprisoned for 52 days, the Alter Rebbe was exonerated and freed of all charges. This was not only a personal victory for Rabbi Schneur Zalman, but on a larger scale, it is the day which vindicated the Chassidic movement and began its further advancement.

The Alter Rebbe felt that his arrest and imprisonment mirrored that which transpired Above, indicating the hesitancy towards the revelation of the inner dimension of Torah, which Chassidut offers. With his release, the Alter Rebbe felt that it pardoned this very manifestation, and continued to further his efforts to increase the spreading of his teachings. One of the Alter Rebbe's most famous books of Chassidut is the Tanya.

Yud Tet Kislev allowed Chassidut to emerge, after much pain and struggle, to grow and develop as an integral part of Torah study. It is the date ascertained as the New Year of Chassidut, and is celebrated by Chassidim worldwide.