Geonim

Geonim (Hebrew: [ɡeʔoˈnim]; Hebrew: גאונים‎‎; also transliterated Gaonim- singular Gaon) were the presidents of the two great Babylonian, Talmudic Academies of Sura and Pumbedita, in the Abbasid Caliphate, and were the generally accepted spiritual leaders of the Jewish community worldwide in the early medieval era, in contrast to the Resh Galuta (Exilarch) who wielded secular authority over the Jews in Islamic lands.

Geonim is the plural of גאון (Gaon') [ɡaˈʔon], which means "pride" or "splendor" in Biblical Hebrew and since the 19th century "genius" as in modern Hebrew. As a title of a Babylonian college president it meant something like "His Excellency".

The Geonim played a prominent and decisive role in the transmission and teaching of Torah and Jewish law. They taught Talmud and decided on issues on which no ruling had been rendered during the period of the Talmud. The Geonim were also spiritual leaders of the Jewish community of their time.

The period of the Geonim began in 589 CE (Hebrew date: 4349), after the period of the Sevora'im, and ended in 1038 (Hebrew date: 4798). The first gaon of Sura, according to Sherira Gaon, was Mar Rab Mar, who assumed office in 609. The last gaon of Sura was Samuel ben Ḥofni, who died in 1034 CE; the last gaon of Pumbedita was Hezekiah Gaon, who was tortured to death by fanatics of the Buyid dynasty in 1040; hence the activity of the Geonim covers a period of nearly 450 years.

...
Wikipedia