which the Babylonian Talmud was developed in the academies founded by Rav and Samuel were followed by five centuries during which it was zealously preserved, studied, expounded in the schools, and, through their influence, recognized by the whole diaspora. Sura and Pumbedita were considered the only important seats of learning: their heads and sages were the undisputed authorities, whose decisions were sought from all sides and were accepted wherever Jewish communal life existed. In the words of the aggadah, "God created these two academies in order that the promise might be fulfilled, that the word of God should never depart from Israel's mouth" ()." The periods of Jewish history immediately following the close of the Talmud are designated according to the titles of the teachers at Sura and Pumbedita; the time of the Geonim and that of the Savoraim. The Savoraim were the scholars whose diligent hands completed the Talmud in the first third of the sixth century, adding manifold amplifications to its text. The title "gaon," which originally belonged preeminently to the head of the Sura Academy, came into general use in the seventh century, under Muslim supremacy, when the official position and rank of the exilarchs and of the heads of the academy were regulated anew. But in order to leave no gaps between the bearers of the title, history must either continue the Savoraim into the seventh century or accept an older origin for the title of gaon. In point of fact, both titles are only conventionally and indifferently applied; the bearers of them are heads of either of the two academies of Sura and Pumbedita and, in that capacity, successors of the Amoraim. The inherited higher standing of Sura endured until the end of the eighth century, after which Pumbedita came into greater importance. Sura will always occupy a prominent place in Jewish history; for it was there that Saadia Gaon gave a new impulse to Jewish lore, and thus paved the way for the intellectual regeneration of Judaism. Pumbedita, on the other hand, may boast that two of its teachers, Sherira and his son Hai Gaon (died 1038), terminated in most glorious fashion the age of the Geonim and with it the activities of the Babylonian academies. When the Abbasid Caliphate and the city of Baghdad declined in the 10th century, many Babylonian Jews migrated to the Mediterranean region. The geonic academies declined and eventually