Rav Yitzchak son of Yeshi was Rosh Yeshiva in Mata Mechasia, received from the Geonim around the year 4640 and died in 4645 [(Sheda"k 37 b), and in Hasa"ch page b: Rav Kamoi in Pumbedita and Rav Yitzchak in Mata Mechasia received their positions in the year 4645, end of quote. And Rash"b, Tzed"h, and the Yuchsin do not bring this Rav Yitzchak.] Aldad HaDani [(see above, year 4632)].