IN the long list of Geonim who stood at the head of the Babylonian academics there is none so distinguished as Saadia ben Joseph ( 892-942), born in the Egyptian province of Fayum, who became head of the Sura Academy in 928. His Arabic translation of the Bible was for the Jews in Mohammedan countries as important as the Septuagint had been for the Jewry of the Hellenistic period. He introduced the principles of deductive logic into all branches of Jewish learning, created an Hebrew philology and became the 'father of the Jewish philosophy of religion'. The values transmitted by Scripture and Jewish tradition were for Saadia, as for all the other Geonim, the unalterable foundations of Judaism, but in examining these values with the methods of Islamic philosophy he succeeded in establishing in his famous philosophical work 'Emunot ve-Deot' (Beliefs and Doctrines), written originally in Arabic, for the first time the mutual relationship between revealed truth and rational thought.
The eminent qualities of Saadia which pervade all his works - his 'wisdom, piety, eloquence, a firm and unbending spirit', for which he was praised already by one of his contemporaries - are reflected also in his letters, of which fortunately some fine specimens have survived.
At the beginning of the tenth century a heated controversy arose in the East over the fixing of the Calendar. As late as 835 the Babylonian Exilarch had recognized that the Palestinian schools were still entitled to fix the days of the new moons and festivals, as they had done for centuries. Soon afterwards, however, with the decay of the Palestinian schools, this privilege was abolished in practice by the authorities in Babylonia. On the other hand, there was a remarkable revival of Jewish learning in Palestine in the first decades of the tenth century, and in 921 Aaron ben Meir, who appears to have been head of a school in Ramlah, proclaimed from the Mount of Olives a revised Calendar according to which the ensuing Passover was to commence on a Sunday, instead of Tuesday as fixed by the Babylonian academies. This announcement gave rise to a controversy which was to be continued for a period of many years and to cause a turmoil in the whole