The enduring vigour of Jewish faith during these centuries is graphically demonstrated by the missionary activity of Jews throughout the ancient Middle East, especially in the Arabian Peninsula. Proud Jewish tribes living in close proximity to each other in the vicinity of Yathrib (later Medina, Muhammad’s home city) engaged in agriculture and commerce and proclaimed the superiority of their monotheistic ethos and eschatology. In Yemen (southwestern Arabia) the last of the Ḥimyarite rulers (reigned from c. 2nd century ce), Dhu Nuwas, proclaimed himself a Jew and finally suffered defeat in approximately 525 as a consequence of Christian influence on the Abyssinian armies. Jewish missionaries, however, continued to compete with Christian missionaries and thus helped to lay the groundwork for the birth of an indigenous Arabic monotheism—Islam—that was to alter the course of world history. The age of the geonim (c. 640–1038) Triumph of the Babylonian rabbinate
The lightning conquests in the Middle East, North Africa, and the Iberian Peninsula by the armies of Islam (7th–8th century) created a political framework for the basically uniform (i.e., Babylonian) character of medieval Judaism. As a “people of the Book” (i.e., of the Bible), the Jews were permitted by the Muslims to live under the same autonomous structure that had developed under Arsacid and Sāsānian rule. The heads of the two principal academies were now formally recognized by the exilarch, and through him by the Muslim caliphs (the civil and religious heads of the Muslim state), as the official arbiters of all questions of religious law and as the religious heads of all Jewish communities that came under Muslim sway. Known as geonim (plural of gaon, “excellency”), they conducted high courts manned by scholars of graded ranks, and they received financial support from Jewish communities assigned to them by the exilarch. Religious questions and contributions were solicited from all Jewish communities, and these, along with formal gaonic replies (responsa), were regularly publicized at the semiannual kalla convocations. Under the strong leadership of Yehudai, gaon of Sura (presided 760–763), the Babylonian rabbinate made vigorous efforts to replace Palestinian usage wherever it was still in vogue—including the study of Palestinian amoraic legal literature—with Babylonian practice and texts, thus making the Babylonian Talmud the unrivalled standard of Jewish norms. The campaign’s success is indicated by the usage of the term Talmud, which, when unqualified, has ever since meant the Babylonian Talmud. Indeed, even in Palestine the Babylonian corpus displaced its older rival and caused the study of Palestinian Talmudic literature to be confined to circles of legal specialists. Anti-rabbinic reactions
The firm—and occasionally oppressive—tactics of exilarchs and geonim generated anti-rabbinic reactions in the form of sectarian and messianic revolts, especially in outlying areas where enforcement was difficult. Inspired in part by ancient Palestinian sectarian doctrines and in part by Muslim usage, the sects were by and large quickly and forcefully suppressed. In the 8th century, according to the traditional Rabbinite account, Anan ben David, a disaffected member of the exilarchic family, founded a dissident group, the Ananites, later known as the Karaites (Scripturalists). The exact relationship between the followers of Anan and the later Karaites, however, remains unclear. The term itself first appeared in the 9th century, when various dissident groups coalesced and ultimately adopted Anan as their founder, though they rejected several of his teachings. The new group advocated a threefold program of rejection of rabbinic law as a human fabrication and therefore as an unwarranted, unauthoritative addition to Scripture; a return to Palestine to hasten the messianic redemption; and a reexamination of Scripture to retrieve authentic law and doctrine. Under the leadership of Daniel al-Qumisi (c. 850?), a Karaite settlement prospered in the Holy Land, from which it spread as far as northwestern Africa and Christian Spain. A barrage of Karaite treatises presenting new views of scriptural exegesis stimulated renewed study of the Bible and the Hebrew language in Rabbinite circles as well. The most momentous consequence of these new studies was the invention of several systems of vocalization for the text of the Hebrew Bible in Babylonia and Tiberias in the 9th and 10th centuries. The annotation of the Masoretic (traditional, or authorized) text of the Bible with vocalic, musical, and grammatical accents in the Tiberian schools of the 10th-century scholars Ben Naftali and Ben Asher fixed the Masoretic text permanently and, through it, the morphology of the Hebrew language for Karaites as well as Rabbinites.
In the face of sectarian challenges, the geonim intensified their efforts against any deviation from Rabbinite norms. They began to issue handbooks of Jewish law that set forth in concise and unequivocal terms the standards for correct practice. A number of these codes, notably the Halakhot gedolot (“Great Laws”), Siddur Rav Amram Gaon (“The Prayer Book of Rav Amram Gaon”; on liturgical practice), and Sheʾeltot (“Disquisitions”) by Aḥa of Shabḥa (c. 680–c. 752), attained authoritative status in local schools and further unified medieval Judaism.
The geonim, however, were powerless to halt several social developments in the 9th century that progressively undermined their hold even on Rabbinite communities. A renaissance of Greek philosophy and sciences in Arabic translation, coupled with the progressive urbanization of the upper classes of all religious and ethnic groups in the centres of political, commercial, and cultural activity, generated a new intelligentsia that cut across religious and ethnic lines. Widespread skepticism concerning basic doctrines of faith such as creation, revelation, and retribution was most poignantly represented by latitudinarianism (the tendency to be flexible and tolerant about deviations from orthodox beliefs and doctrines) and by antinomian gnostic groups that denied divine providence and omniscience (see antinomianism). Ḥiwi al-Balkhī, a 9th-century skeptical Jewish pamphleteer, scandalized the faithful by openly attacking the morality of Scripture and by issuing for schools an expurgated edition of the Bible that omitted “offensive” material (e.g., alleged stories of God acting dishonestly). A mystifying Hebrew tract titled Sefer yetzira" class="md-crosslink">Sefer yetzira (“Book of Creation”) posited in terse and enigmatic epigrams a novel theory of creation that betrayed Neoplatonic influence. Karaites joined philosophically oriented intellectuals in heaping scorn on popular Rabbinite customs that smacked of superstition and, above all, on Talmudic homilies that referred to God in anthropomorphic terms.
Gaonic difficulties were compounded by the rise in North Africa and Spain of populous and wealthy Jewish communities that, thanks to the development of their own local schools and talent, ignored the Babylonian academies or favoured one over the other with religious queries and, in consequence, with financial contributions. To the delight of dissidents and the chagrin of the faithful, competition between the Babylonian academies turned to internecine hostility. Occasional revolts against exilarchic taxation and administration in outlying areas of Persia had to be quelled with armed force. The Palestinian Rabbinites had revived their own academies, and their presidents now not only appealed for support in other Diaspora lands but challenged the authority of the Babylonians to serve as final arbiters on matters of public import, such as the regulation of the calendar. By 900 the Rabbinite community of Babylonia was in a state of chaos and dissolution. The gaonate of Saʿadia ben Joseph