Isamar Rosenbaum
Isamar Rosenbaum (1886–1973) was a Hasidic rebbe of the Hasidic dynasties of Nadvorna and Kretshnif. He was the son of Rabbi Meyer Rosenbaum (1852 - June 29 1908) of Kretshniff, who in turn was a son of Rabbi Mordechai of Nadvorna (1824–1894). Rosenbaum became a rebbe at the age of fifteen and, at his father's behest, moved to Czernowitz where he served as a chasidic rebbe. In the Nadvorna dynasty, all children of the rebbes open their own chasidic courts, even during their fathers' lifetime. His wife, Malka, was the daughter of Rebbe Usher Yeshaya Rubin of Kolbuszowa, Galicia.