His closest colleagues were Rav Ashi and Amemar. The three of them are described together in their studies, meals, and visits to the court of Yazdegerd I.[3]
He headed the Yeshiva of Pumbedita, and according to the book "Seder Tannaim ve-Amoraim", previous to Rav Aha b. Rava. In the Iggeret Rav Sherira Gaon (French version), he is not mentioned as a head of a Yeshiva, but in later sources he is noted as Mar Zutra, Head of a Yeshiva.