Mar Rav Yehuda bar Mar Rav Nachman became head of the yeshiva in Sura from year 4515 for two and a half years and composed Halachot Pesukot, and from Halachot Gedolot he gathered. [Rash"b Yuchsin wrote that he was from Pumbedita and there was no one at that time who excelled in wisdom in Sura like him, even though his schooling was complete. He was an Exilarch and a judge and the light of our eyes, and he and his brother (see above year 4518) were Geonim in both yeshivot at one time.

In Yuchsin in the order of tradition from the Rama"n, and after him Rav Ochna'i, 69, and Mar Rav Yehuda bar Mar Rav Ochna'i whom Tzemach David mentions is missing. And in Shada"k page 36b and following, Rav Yehuda was head of the yeshiva in Mata Mechasia and died in year 4517. They received from the Geonim who preceded them as in year 4500. Rav Mari was a blind old man and despite this he composed many halachot.

In his days one student went out to bad culture. After him Rav Mari bar Rav Mesharsheya died in year 4542, end quote. Surely 69 in what is written 'Rav Mari was a blind old man' is an error, because Yuchsin and Rash"b wrote this about Rav Yehuda. Also what Yuchsin wrote 'he died in year 4552' and Shada"k wrote he died in year 4517 - in both cases there is an error of 69, because he only ruled for two and a half years.

And what is written that in the days of Rav Mari one student went out, etc. - Yuchsin, section 5 in the order of the Geonim, generation 2, and Rash"b wrote: In the days of Mar Rav Yehuda, Anan and his son Shaul went out. They were ministers from the seed of the House of David but they were not assisted from Heaven for ordination. He became an elder of rebellion according to the House of David and strengthened the faith of the Karaites, end quote, and in Tzemach David he wrote:] In his days there was Anan, who was at first a Torah scholar but because of a disqualifying flaw found in him he was not ordained as a Gaon.

He became an elder of rebellion according to the House of David because he strengthened the Sadducees who had declined from the destruction until Anan came and strengthened them.