שאלות ותשובֿות אויף בראשית 12:18

And Huna bar Natan (הונא בר נתן), who was the Exilarch in those days, and Maremar (מרימר) and Mar Zutra (מר זוטרא), who were after him, all submitted to Rav Ashi (רב אשי) and established their festivals in Mata Mehasya (מתא מחסיא). As we say: Rav Aha son of Rava (רב אחא בריה דרבא) said, "We can also say, from the days of Rabbi until Rav Ashi, we have not found Torah and greatness in one place. And behold, Huna bar Natan submitted to Rav Ashi." And since they established the festivals of the Exilarchs in Mata Mehasya, the authorities of Pumbedita needed to go there on the Sabbath of 'Lech Lecha', which was the festival Sabbath of the Exilarchs, and it became fixed that most of the Exilarchs would go there.