Samuel became the acknowledged leader of the Jewish community in Babylon. A friend and colleague of Rav, he lived and taught in Nahardea where he was head of the academy. He was also an astronomer who composed a fixed calendar. He did not publish it, however, out of respect for the Patriarchate in Eretz Israel. In monetary and civil matters his rulings were accepted as binding. He also instructed Jews to adopt the laws of whichever land they dwelt in (Dina d'malchuta Dina), thus preparing them for survival in foreign environments. He served for only seven years.