Medieval Judaism flourished in the two great cultural spheres of the Muslim and Christian world. In Islamic societies, both Jews and Christians were subjects under the status of dhimmi, according to which they had to submit to political and religious power (they had to pay certain taxes and were subject to certain discriminating duties). But, as people of the Book, they were protected and allowed to practice their religion within certain limits. In the first few centuries when Judaism existed in Muslim lands, there was an intellectual and religious boom whose influence extended beyond the Jewish world. During this period, Talmudic commentaries and major spiritual works were produced; this was also the time of the geonim, the heads of the Babylonian religious academies. If Hebrew was the language of the liturgy, Arabic was that of scholars.
After the 12th century, other Jewish intellectual centres were established, formalizing the codes and rituals of Judaism. Spain and North Africa became key centres of influence in which both Talmudic and profane studies, including medicine, astronomy or humanities, flourished. The production of literary works in Hebrew thrived thanks to personalities such as Judah Halevi. But the great figure of this period was Moses ben Maimon, known as Maimonides (approximately 1135-1204). A man of science, a doctor, but also a philosopher and a Talmudic scholar, Maimonides’ influence lasted for many centuries and expanded beyond the Jewish world. He introduced Aristotelian philosophy as an exegetical method of the biblical text and is considered the father of a rationalist approach in Judaism.
Emerging as a regional centre of Judaism, Spain, especially the city of Gerona, became a place that favoured the expression of a Kabbalistic approach to the biblical text. This esoteric tradition in Judaism, whose followers believe that it brings them closer to God, gave birth to Sefer Ha-Zohar (The Book of Splendour). It was written in Aramaic and offered an esoteric and mystical exegesis of the biblical text. At end of the Middle Ages, the expulsion of the Jews from Spain did not put an end to the popularity of the Kabbala, which continued throughout the centuries and spread into other places in the Jewish world.
In Christianity, the Jews who pre-existed the Christianization of the West, lived through different periods of relative tolerance, or experienced violent and recurring persecutions. After the 10th and 11th centuries, the Jewish communities of Europe went through a period urbanization and Jews with very diverse professions participated in the economic and cultural development of the Christian societies in Europe. However, Jews also faced particularly difficult periods, starting from the Crusades (between 1096 and 1291) to which they fell victim. Following a decision of the fourth Council of the Lateran (1215), they were subject to persecutory measures, such as the wearing of symbols, which differentiated them from Christians. The end of the Middle Ages in certain European countries was a period of rising violence towards Jews, in Spain and Portugal for example, where Jews were forced to convert to Christianity, but were also suspected of continuing to secretly practice their first religion (the conversos or new Christians). In the end of the 13th century and in the 14th and 15th centuries, the expulsions of Jews from western Europe increased. This was the case in France, in 1306, under the rule of Philip the Fair, but particularly in regions all over Spain and Portugal at the end of the 15th century. The Jews of the Iberian peninsula (or Sephardic Jews) moved around the Mediterranean basin, particularly in North Africa and the Levant, but also in the Balkans and the Netherlands. In the end of the Middle Ages, the first reserved areas, the ghettos, emerged (the first one was in Venice in 1516), where Jews were forced to live. In the end of the 16th century, the centre of gravity for Jewish diasporas moved from the western to the eastern part of what was a Christian Europe.
In the last centuries of the Middle Ages, intense reflections and exegeses were produced through several Talmudic commentaries. For example, Rachi de Troyes (1040-1105), a rabbi and scholar, wrote important Talmudic commentaries, as well as a biblical exegesis, which became a reference work in the entire Jewish world. Rachi was also a great intermediary figure between Jews and Christians and his work influenced several great Medieval Christian figures.
After the 16th century, various conversos secretly practiced Judaism (the marranos) in France, including in Bordeaux, Bayonne and Rouen. The Jews who were expelled from Spain and Portugal headed to Amsterdam in such great numbers that it was considered the capital of the unified provinces of “North Jerusalem”, from where the first Jews left to settle in South America and the east coast of the United States. The Jews of the Ottoman Empire, many of whom were also from the Iberian peninsula, preserved the memory and cultural links with their country of origin by keeping the Sephardic-Jewish language alive. The tradition of the Kabbala, which was prevalent in the Sephardic world of the Middle Ages, flourished after the 16th century, especially in the city of Safed. The Sephardic norm of the Halakha prevailed in the battered Ashkenazi world through the treatise of Shulhan Arukh (Set Table) by Jospeh Caro, published in the 16th century.
The Jews suffered a great deal from the backlash of the Catholic reaffirmation during the Counter-Reformation. Even though Luther was initially tolerant towards them, he hardened his stance when he realized that they were not going to join the Protestant movement. In central Europe Ashkenazi Judaism experienced its greatest moment of glory in the 17th century, especially in Poland and in Bohemia, even though ghettos and restrictive policies spread in the middle of the century. The pogroms that were committed in Poland, particularly under the Russian occupation, reignited misery, but also despair among the Jewish communities in central and eastern Europe. It was this terrible context that favoured in the second half of the 17th century, the rise of messianic theories, some of which flourished. For example, Sabbatai Tsvi (1626-1676), a Jew born in Smyrna, claimed that he was the messiah of Israel, and, in the middle of a period of turmoil in the Ashkenazi Jewish world, he was partly successful, despite the fact that he was condemned by most rabbis. After he was denounced by the Jewish authorities and sent into exile, Sabbatai Tsvi ended up converting to Islam. But his death in 1676 did not prevent the resurgence of the messianic movements that left a strong mark on Jewish conscience and history in the 18th century.