Born in the city of Izmir (Smyrna) in 1626, Shabbetai Tsvi, while still in his twenties, pronounced God’s ineffable name and celebrated the three major festivals in a single week; later he married a prostitute. Only after that did he meet a mystic and self-proclaimed prophet named Nathan of Gaza who convinced him that he was the messiah. By the mid-1660s, much of European and Middle Eastern Jewry had become convinced that Shabbetai Tsvi was in fact going to lead them back the Land of Israel. They were thus shocked and disappointed when he converted to Islam—to avoid execution by the Ottoman sultan—but a minority of his followers interpreted this decision as a kabbalistic tactic to hasten the redemption. The distinguished medieval historian David Berger tells the story in detail, and seeks to explain why Sabbatianism had a degree of success unparalleled either before or since. (Audio, 64 minutes.)
Read more on YU Torah: https://www.yutorah.org/lectures/lecture.cfm/990165/rabbi-david-berger/shabbetai-zvi-and-the-most-successful-messianic-movement-in-jewish-history-after-the-first-century/