In the ninth century we meet the first traces of a scientific literature. Prominent here is Saadya Gaon (892-942), born in Fayum, and called to Sura as Gaon, quite an unusual event. His literary activity extends over the whole field of Jewish literature. He wrote commentaries on the Bible besides an Arabic translation, and on Talmudic topics. He also composed religious hymns, but the most important of all his works is his אמונות ודעות (Dogma and Science), the first attempt at a scientific apology for Judaism from a philosophical point of view. His independence brought him into conflict with the Exilarch David ben Zakkai, to whose dictates he would not submit in a matter which he regarded as unjust; consequently he was deposed. Saadya contended that this act was illegal and excommunicated the Exilarch. The latter proved stronger and Saadya was forced into exile. Later on, however, they became reconciled, and Saadya was reinstated (934).
The last two Gaonim of any importance lived in Pumbeditha. They were Sherira, who died in 999, and his son, Hay Gaon, who died in 1038. From the former we possess a very important historical treatise on the development of Rabbinic law known as the epistle of Sherira Gaon. It was written at the request of a man in Morocco, and was inspired by apologetic motives to prove that the law had been handed down unaltered from generation to generation. From Hay Gaon we have various Talmudic works, many responsa, and a didactic poem. Their contemporary was Samuel ibn Hofni, a rationalistic writer, who rejected the belief in the miracles related in the Talmud. Otherwise the age of the Gaonim is characterized by a blind faith, not only in Bible and Talmud, but also in popular superstitions and in the preservation of superstitious customs. Hay was succeeded by Hezekiah, who after holding his office for two years was put to death by the Caliph in 1040. After this time the office lost all significance. Names of a few of those who held office after this time are found, but nothing is known of their activity, nor has any literary work of this age come down to us.
The blind faith which characterized the period of the Gaonim aroused considerable opposition, culminating in the foundation of a religious sect called the Karaites, בני מקרא “Sons of the Bible.” Their founder was Anan ben David (760) who claimed the Bible as the only authority for faith and practice, and therefore rejected all Rabbinic law. His successors founded a congregation in Jerusalem, and very soon spread in the East. The most prominent teachers of the Karaites are Benjamin of Nehawend, and Salman ben Jeroham, the latter of whom carried on a literary controversy with Saadya. Judah Hadassi, in the thirteenth century wrote אשכל הכפר the standard work of the Karaite law, written in rhymed prose. Other important Karaite scholars are Aaron ben Elijah, who died in 1369, the author of גן עדן, a compendium of the religious law, and עץ חיים, a work on religious philosophy.
In the fifteenth century Elijah Bashjazi wrote another compendium of the Karaite religion entitled אדרת אליהו. By this period a large Karaite community settled in Lithuania, where Isaac of Troki wrote a very able polemical treatise directed against Christianity, known as חזוק אמונה. In 1698, Jacob Trigland, professor at Leyden, made inquiries concerning the Karaites by means of a letter addressed to their chief sent through an ambassador to Poland. He received a reply, דודמרדכי, written by Mordecai ben Nissim. This was, for a long time, the only source of information on the history of the Karaites. The last Karaite author of any consequence was Abraham Firkovitch (1787-1874) of Russia, who discovered and published important Karaite documents. Some of these, however, he forged in the interest of the Karaite claim that the Karaites represent the original Judaism from which the Rabbanites seceded.
At the same time that the Karaite schism occurred, the Chazars, a Tartar tribe, were converted to Judaism. Reports of the existence of a Jewish kingdom had reached the Jews of Western Europe. Hasdai ibn Shaprut wrote a letter of inquiry on this. He received a reply from the King of the Chazars, and these two letters are the chief source of information concerning this remarkable event. Toward the end of the tenth century the kingdom of the Chazars was conquered by the Russians. Judah Halevi, who wrote his Kuzari about 1140, used the story of the conversion of the Chazar King in the form of a philosophic dialogue between him and the rabbi who converted him. The knowledge he had of an independent Jewish state was the basis of the fanciful reports circulated by an adventurer who called himself Eldad Hadani and pretended to be a descendant of one of the lost ten tribes. Their habitation and modes of life he described in a book. He appeared in the tenth century in Morocco, but nothing is known as to what finally became of him.
In the ninth century, the literature of religious hymns, Piyut, begins. The authors of these are called Payetanim (poets). Their works are characterized by arbitrary handling of the Hebrew grammar, by the creation of new words in an arbitrary style, and finally, by obscure allusions to the Midrash. The oldest of these poets are Jose ben Jose and Jannai. Their successor, Eleazar ben Kallir, is the most prolific of all. Of his life we know nothing with certainty.
The literary activity of the Jews of Europe began in the ninth century. The first work is probably the Josippon, a history of the Jews from the destruction of Babylon by Cyrus to the downfall of Jerusalem in 70, which was ascribed to Josephus Flavius. Another anonymous writer, who lived in Italy in the ninth century, is the author of the Midrash, called Pirke Rabbi Eliezer. But the first Jewish author who lived in Europe, known by name, is Sabbatai Donolo (913-982), who wrote on medicine, astrology, and Kabbala.