The Sabbateans (or Sabbatians) were a variety of Jewish followers, disciples, and believers in Sabbatai Zevi (1626-1676),  a Sephardic Jewish rabbi and Kabbalist who was proclaimed to be the Jewish Messiah in 1666 by Nathan of Gaza.
Vast numbers of Jews in the Jewish diaspora accepted his claims, even after he outwardly became an apostate due to his forced conversion to Islam in the same year. Sabbatai Zevi's followers, both during his proclaimed messiahship and after his forced conversion to Islam, are known as Sabbateans. Part of the Sabbateans lived on until well into 21st-century Turkey as descendants of the Dönmeh.
Sabbatai Zevi was a Sephardic ordained rabbi from Smyrna (now ?zmir, Turkey). A kabbalist of Romaniote origin, Zevi, who was active throughout the Ottoman Empire, claimed to be the long-awaited Jewish Messiah. He was the founder of the Sabbatean movement, whose followers subsequently were to be known as Dönmeh "converts" or crypto-Jews.
In February 1666, upon arriving in Constantinople, Sabbatai was imprisoned on the order of the grand vizier Köprülüzade Faz?l Ahmed Pasha; in September of that same year, after being moved from different prisons around the capital to Adrianople (the imperial court's seat) for judgment on accusations of fomenting sedition, Sabbatai was given by the Grand Vizier, in the name of the Sultan of the Ottoman Empire, Mehmed IV, the choice of either facing death by some type of ordeal, or of converting to Islam. Sabbatai seems to have chosen the latter by donning from then on a turban. He was then also rewarded by the heads of the Ottoman state with a generous pension for his compliance with their political and religious plans.
Sabbatai's conversion to Islam was extremely disheartening for the world's Jewish communities. Among the masses of the people the greatest confusion reigned. In addition to the misery and disappointment from within, Muslims and Christians jeered at and scorned the credulous and duped Jews.
In spite of Sabbatai's apostasy, many of his adherents still tenaciously clung to him, claiming that his conversion was a part of the Messianic scheme. This belief was further upheld and strengthened by the likes of Nathan of Gaza and Samuel Primo, who were interested in maintaining the movement.
Many within Zevi's inner circle followed him into Islam, including his wife Sarah and most of his closest relatives and friends. Nathan of Gaza, the scholar closest to Zevi, who had caused Zevi to reveal his Messiahship and in turn became his prophet, never followed his master into Islam but remained a Jew, albeit excommunicated by his Jewish brethren.
After Sabbatai Zevi's apostasy, many Jews, although horrified, clung to the belief that Zevi could still be regarded as the true Jewish Messiah. They constituted the largest number of Sabbateans during the 17th and 18th centuries. By the 19th century, Jewish Sabbateans had been reduced to small groups of hidden followers who feared being discovered for their beliefs, that were deemed to be entirely heretical and antithetical to Rabbinic Judaism. These very Jews fell under the category of "sectarian" Sabbateans, which originated when many Sabbateans refused to accept that Zevi's feigned apostasy might have been indicative of the fact that their faith was genuinely an illusion.
Another large group of Sabbateans after Zevi's apostasy began to view Islam in an extremely negative light. Polemics against Islam erupted directly after Zevi's forced conversion. Some of these attacks were considered part of a largely anti-Sabbatean agenda. Accusations coming from anti-Sabbatean Jews revolved around the idea that Sabbatai Zevi's feigned conversion to Islam was rightfully an indicator of a false claim of Messianship.
Inside the Ottoman Empire, those followers of Zevi who had converted to Islam but who secretly continued Jewish observances and Brit Mila became known as the Dönme (Turkish: dönme "convert"). There were some internal sub-divisions within the sect, according to the geographical locations of the group, and according to who the leaders of these groups were after the death of Sabbatai Zevi.
The Emden-Eybeschutz controversy was a serious rabbinical disputation with wider political ramifications in Europe that followed the accusations by Rabbi Jacob Emden (1697-1776), a fierce opponent of the Sabbateans, against Rabbi Jonathan Eybeschutz (1690-1764) whom he accused of being a secret Sabbatean.
The Emden-Eybeschutz controversy arose concerning the amulets which Emden suspected Eybeschutz of issuing. It was alleged that these amulets recognized the messianic claims of Sabbatai Zevi. Emden then accused Eybeschutz of heresy. Emden was known for his attacks directed against the adherents, or those he supposed to be adherents, of Sabbatai Zevi. In Emden's eyes, Eybeschutz was a convicted Sabbatean. The controversy lasted several years, continuing even after Eybeschutz's death.
Emden's assertion of heresy was chiefly based on the interpretation of some amulets prepared by Eybeschutz, in which Emden professed to see Sabbatean allusions. Hostilities began before Eybeschutz left Prague; when Eybeschutz was named chief rabbi of the three communities of Altona, Hamburg, and Wandsbek in 1751, the controversy reached the stage of intense and bitter antagonism. Emden maintained that he was at first prevented by threats from publishing anything against Eybeschutz. He solemnly declared in his synagogue the writer of the amulets to be a Sabbatean heretic and deserving of ?erem (excommunication).
In July 1725, the Ashkenazic beit din of Amsterdam had issued a ban of excommunication on the entire Sabbatian sect (kat ha-ma'aminim). Writings of Sabbatian nature found by the beit Din at that time were attributed to Eybeschutz. In early September, similar proclamations were issued by the batei din of Frankfurt and the triple community of Altona, Hamburg, and Wandsbeck. The three bans were printed and circulated in other Jewish communities throughout Europe. Rabbi Ezekiel Katzenellenbogen, the chief rabbi of the Triple Community and Rabbi Moses Hagiz  were unwilling to attack Eybeschütz publicly, mentioning that "greater than him have fallen and crumbled" and that "there is nothing we can do to him". However, Rabbi Katzenelenbogen stated that one of the texts found by the Amsterdam beit din "Va-Avo ha-Yom el ha-Ayyin" was authored by Jonathan Eybeschütz and declared that the all copies of the work that were in circulation should be immediately burned. Emden later suggested that the rabbis decided against attacking Eybeschutz out of a reluctance to offend his powerful family and a fear of rich supporters of his living in their communities. As a result of Eyberschutz and other rabbis in Prague formulating a new (and different) ban against Sabbatianism in September of that year his reputation was restored and Eybeschutz was regarded as having been totally vindicated. The issue was to arise again, albeit tangentially, in the 1751 dispute between Emden and Eyberschutz.
The controversy was a momentous incident in Jewish history of the period, involving both Yechezkel Landau and the Vilna Gaon, and may be credited with having crushed the lingering belief in Sabbatai current even in some Orthodox circles. In 1760 the quarrel broke out once more when some Sabbatean elements were discovered among the students of Eybeschutz' yeshiva. At the same time his younger son, Wolf, presented himself as a Sabbatean prophet, with the result that the yeshiva was closed.
Some scholars see seeds of the Hasidic movement within the Sabbatean movement. When Hasidism began to spread its influence, a serious schism evolved between the Hasidic and non-Hasidic Jews. Those who rejected the Hasidic movement dubbed themselves as misnagdim ("opponents").
Critics of Hasidic Judaism[who?] expressed concern that Hasidism might become a messianic sect as had occurred among the followers of both Sabbatai Zevi and Jacob Frank. However the Baal Shem Tov, the founder of Hasidism, came at a time when the Jewish masses of Eastern Europe were reeling in bewilderment and disappointment engendered by the two Jewish false messiahs Sabbatai Zevi (1626-1676) and Jacob Frank (1726-1791) in particular.
Some scholars have noted that the Sabbatean movement in general fostered and connected well with the principles of modern secularism. Related to this is the drive of the Donmeh in Turkey for secularizing their society just as European Jews promoted the values of Age of Enlightenment and its Jewish equivalent the haskalah.
Rabbi Shabbetai Tzevi of Smyrna (1626-76), who proclaimed himself messiah in 1665. Although the "messiah" was forcibly converted to Islam in 1666 and ended his life in exile 10 years later, he continued to have faithful followers. A sect was thus born and survived, largely thanks to the activity of Nathan of Gaza (c. 1644-90), an unwearying propagandist who justified the actions of Shabbetai Tzevi, including his final apostasy, with theories based on the Lurian doctrine of "repair". Tzevi's actions, according to Nathan, should be understood as the descent of the just into the abyss of the "shells" in order to liberate the captive particles of divine light. The Shabbetaian crisis lasted nearly a century, and some of its aftereffects lasted even longer. It led to the formation of sects whose members were externally converted to Islam--e.g., the Dönmeh (Turkish: "Apostates") of Salonika, whose descendants still live in Turkey--or to Roman Catholicism--e.g., the Polish supporters of Jacob Frank (1726-91), the self-proclaimed messiah and Catholic convert (in Bohemia-Moravia, however, the Frankists outwardly remained Jews). This crisis did not discredit Kabbalah, but it did lead Jewish spiritual authorities to monitor and severely curtail its spread and to use censorship and other acts of repression against anyone--even a person of tested piety and recognized knowledge--who was suspected of Shabbetaian sympathies or messianic pretensions.CS1 maint: extra text: authors list (link)
Born in Smyrna in 1626, he showed early promise as a Talmudic scholar, and even more as a student and devotee of Kabbalah. More pronounced than his scholarship were his strange mystical speculations and religious ecstasies. He traveled to various cities, his strong personality and his alternately ascetic and self-indulgent behavior attracting and repelling rabbis and populace alike. He was expelled from Salonica by its rabbis for having staged a wedding service with himself as bridegroom and the Torah as bride. His erratic behavior continued. For long periods, he was a respected student and teacher of Kabbalah; at other times, he was given to messianic fantasies and bizarre acts. At one point, living in Jerusalem seeking "peace for his soul," he sought out a self-proclaimed "man of God," Nathan of Gaza, who declared Shabbetai Zvi to be the Messiah. Then Shabbetai Zvi began to act the part [...] On September 15, 1666, Shabbetai Zvi, brought before the sultan and given the choice of death or apostasy, prudently chose the latter, setting a turban on his head to signify his conversion to Islam, for which he was rewarded with the honorary title "Keeper of the Palace Gates" and a pension of 150 piasters a day. The apostasy shocked the Jewish world. Leaders and followers alike refused to believe it. Many continued to anticipate a second coming, and faith in false messiahs continued through the eighteenth century. In the vast majority of believers revulsion and remorse set in and there was an active endeavor to erase all evidence, even mention of the pseudo messiah. Pages were removed from communal registers, and documents were destroyed. Few copies of the books that celebrated Shabbetai Zvi survived, and those that did have become rarities much sought after by libraries and collectors.
At the command [of the sultan], Shabbetai was now taken from Abydos to Adrianople, where the sultan's physician, a former Jew, advised Shabbetai to embrace Islam as the only means of saving his life. Shabbetai realized the danger of his situation and adopted the physician's advice. On the following day [...] being brought before the sultan, he cast off his Jewish garb and put a Turkish turban on his head; and thus his conversion to Islam was accomplished. The sultan was much pleased, and rewarded Shabbetai by conferring on him the title (Mahmed) "Effendi" and appointing him as his doorkeeper with a high salary. [...] To complete his acceptance of Mohammedanism, Shabbetai was ordered to take an additional wife, a Mohammedan slave, which order he obeyed. [...] Meanwhile, Shabbetai secretly continued his plots, playing a double game. At times he would assume the role of a pious Mohammedan and revile Judaism; at others he would enter into relations with Jews as one of their own faith. Thus in March, 1668, he gave out anew that he had been filled with the Holy Spirit at Passover and had received a revelation. He, or one of his followers, published a mystic work addressed to the Jews in which the most fantastic notions were set forth, e.g., that he was the true Redeemer, in spite of his conversion, his object being to bring over thousands of Mohammedans to Judaism. To the sultan he said that his activity among the Jews was to bring them over to Islam. He therefore received permission to associate with his former coreligionists, and even to preach in their synagogues. He thus succeeded in bringing over a number of Mohammedans to his cabalistic views, and, on the other hand, in converting many Jews to Islam, thus forming a Judæo-Turkish sect (see Dönmeh), whose followers implicitly believed in him [as the Jewish Messiah]. This double-dealing with Jews and Mohammedans, however, could not last very long. Gradually the Turks tired of Shabbetai's schemes. He was deprived of his salary, and banished from Adrianople to Constantinople. In a village near the latter city he was one day surprised while singing psalms in a tent with Jews, whereupon the grand vizier ordered his banishment to Dulcigno, a small place in Albania, where he died in loneliness and obscurity.