Sabbateans

[1][2] 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.

[1][3] In the late 17th century, northern Italy experienced a surge of Sabbatean activity, driven by the missionary efforts of Abraham Miguel Cardoso.

Around 1700, a radical faction within the Dönmeh movement, led by Baruchiah Russo, emerged, which sought to abolish many biblical prohibitions.

Concurrently, anti-Sabbatean literature emerged, leading to a notable dispute between Rabbi Jacob Emden (Ya'avetz) and Jonathan Eybeschuetz.

[8] In February 1666, upon arriving in Constantinople, Sabbatai was imprisoned on the order of the grand vizier Köprülüzade Fazıl 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.

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.

[14] 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.

In July 1725, the Ashkenazic beth din of Amsterdam had issued a ban of excommunication on the entire Sabbatian sect (kat ha-ma’aminim).

[16] In early September, similar proclamations were issued by the batei din of Frankfurt and the triple community of Altona, Hamburg, and Wandsbeck.

[18] However, Rabbi Katzenelenbogen stated that one of the texts found by the Amsterdam beit din Va'avo Hayom el Ha'Ayin "And I Came This Day into the Fountain" was authored by Jonathan Eybeschütz and declared that the all copies of the work that were in circulation should be immediately burned.

[19][20] 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.

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.

[24] Related to this is the drive of the Dönmeh in Turkey for secularizing their society just as European Jews promoted the values of Age of Enlightenment and its Jewish equivalent the haskalah.