Rabbi Chaim Tzvi Teitelbaum (December 28, 1879 – January 21, 1926) (6 shevat 5686 on the Hebrew calendar), the Sigheter Rebbe, author of Atzei Chaim, was the oldest son of Rabbi Chananya Yom Tov Lipa Teitelbaum, the Kedushas Yom Tov. He was the elder brother of Rabbi Joel Teitelbaum, and the father of Moshe Teitelbaum, both rebbes of Satmar.