Books by Moshe Idel are often a feast for scholars, and his latest one, Saturn's Jews: On the Witches' Sabbat and Sabbateanism (New York: Continuum, 2011), is no exception. Idel's starting point is not absolutely new. During the witch scares, both Medieval and modern, some Christians argued, with clear anti-Semitic overtones, that witchcraft had a Jewish origin. The name of the witches' sabbat, they argued, came from the Jewish holy day, the Sabbath, and both sabbat and Sabbath started on Friday.

Although Idel, following Carlo Ginzburg, does believe that there was some reality in witchcraft rituals and that they were more than a figment of the Inquisitors' imagination, he strongly argues that the etymology deriving sabbat from Sabbath was purely fictional. To the extent it was real, witchcraft traced its roots in folkloric rituals and perhaps mystery traditions of Asian origins, without any Jewish contribution. Idel's book, however, is really about a different subject matter. The connection between two terms, Judaism and witchcraft - sabbat and Sabbath - did appear as believable because of a third term, the planet Saturn. Both Hellenistic and Arab astrology believed that peoples had their own presiding planet, and indicated Saturn as the planet of the Jews. Since Saturn was also the planet presiding over the dark arts and witchcraft, the latter's connection with the Jews became believable. And the Jews indeed observed as their holy day Saturday, i.e. Saturn's day. Tragically for the Medieval persecutions of the Jews, the planet was also associated with the plague.

Idel notes that the few historians who mentioned the Saturn connection normally associated it with an anti-Semitic Moslem or Christian astrology. But they neglected, he argues, that a whole school of Jewish sages and philosophers, well versed in astrology and combining astrosophical themes with the Kabbalah, also took for granted that Saturn was indeed the planet presiding over Israel. Idel particularly studies Abraham ibn Ezra (Abenezra, 1089-1164), Abraham Abulafia (1240-dopo il 1291), Joseph Ashkenazi. (ca. 1270 - ca. 1325), and Yohanan Alemanno (1435-1504). According to Idel, the ideas of these sages also influenced the Ba'al Shem Tov (1699-1760), the very founder of Hasidism, and extended their influence into the 20th century via such important Jewish intellectuals as Franz Kafka (1883-1924) and Walter Benjamin (1892-1940). All these thinkers associated with the Jews, «born under Saturn», an inclination toward magic and esotericism and the typical «Saturnine» character, melancholy.

This current, Idel clarifies, never represented the majority of Judaism and was severely criticized by Maimonides (1138-1204). Idel, however, mentions the useful sociological concept of a «secondary elite» in order to designate a group which remains a minority, yet exerts a long-lasting influence. He also insists on the historical importance of misunderstandings. It was, he claims, a misunderstanding for these authors to believe that the relationship between the Jews and Saturn was a proven «scientific» fact. In fact, it may well have been a mere anti-Semitic argument first by Hellenistic and then by Moslem and Christian astrologers. However, these Jewish sages accepted the connection, and tried to deal with the consequences. Some argued that the potentially evil influence of Saturn was yet another trial for the Jews who, by overcoming it, confirmed their loyalty to God. Others insisted that Saturn also offered positive inclinations: a predisposition to mysticism, literary and artistic creativity, and even spiritual greatness.

Hence the further idea that the coming Messiah will have a special relationship with Saturn, which - Idel claims - is one of the factors explaining both the personality and the success of Sabbatai Zevi (1626-1676), the 17th century adventurer who claimed to be the long awaited Messiah. Not only, Idel argues, Zevi made the most of his first name, Sabbatai, connected with bot Sabbath and Saturn, but his followers believed this name to be quite significant, thus evidencing the continuing influence of the «secondary elite» in larger Jewish circles. Idel also mentions the controversies between two rival groups of (mostly Jewish) historians, those associated with the Warburg Institute in London and those working at the Hebrew University in Jerusalem under Idel's own mentor, Gershom Scholem (1897-1982). It is because of this controversy that, while the Warburg scholars produced wonderful studies of Saturn and Scholem of Sabbatai Zevi, the latter ignored the role of Saturn in Zevi's success, and the former did not mention Zevi at all. A pity, Idel argues, since the Saturn-witchcraft-Zevi connection is a fascinating and not unimportant topic in Jewish intellectual history.