Sabbateans (Sabbatians) is a complex general term that refers to a variety of followers of, disciples and believers in Sabbatai Zevi (1626–1676), a Jewish rabbi who was proclaimed to be the Jewish Messiah in 1665 by Nathan of Gaza. Vast numbers of Jews in the Jewish diaspora accepted his claims, even after he became a Jewish apostate with his conversion to Islam in 1666. Sabbatai Zevi's followers, both during his "Messiahship" and after his conversion to Islam, are known as Sabbateans. They can be grouped into three: "Maaminim" (believers), "Haberim" (associates), and "Ba'ale Milhamah" (warriors).
Part of the Sabbateans lived on until well into the 20th century as Dönmeh.
In Jewish history many Jews post Sabbatai Zvi's apostasy, although horrified, clung to the belief that Zvi could still be regarded as the true Jewish messiah. They constituted the largest number of Sabbateans during the seventeenth and eighteenth centuries. By the nineteenth 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 classical Judaism. These very Jews fell under the category of Sectarian Sabbateans which was born when many Sabbateans refused to accept that Zvi's apostasy might have been indicative of the fact that their faith was genuinely an illusion.
Another large group of Sabbateans succeeding the apostasy began to view Islam in an extremely negative light. Polemics against Islam erupted directly after Zvi's conversion. Some of these attacks were considered part of a largely Anti-Sabbatean agenda. Accusations coming from Anti-Sabbateans revolved around the idea that Sabbatai Zvi's conversion to Islam was rightfully an indicator of a false claim of messianism.
Jewish historians have stated that it is hard to describe the national sense of shock and trauma that set in when the masses of Jews all over the world learned that someone as famous as Sabbatai Zevi had officially abandoned his faith for Islam. However, the fact remains that Zevi is the most famous Jew to have become a Muslim, which is also what the term Sabbatean has come to denote. 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.