Sabbatai Zevi (Hebrew: שַׁבְּתַי צְבִי, other spellings include Shabbetai Ẓevi, Shabbeṯāy Ṣeḇī, Shabsai Tzvi, and Sabetay Sevi in Turkish) (August 1, 1626 – c. September 17, 1676) was a Sephardic ordained rabbi, though of Romaniote origin and a kabbalist, active throughout the Ottoman Empire, who claimed to be the long-awaited Jewish Messiah. He was the founder of the Sabbatean movement.
In February 1666, upon arriving in Constantinople, Sabbatai was imprisoned on the order of the grand vizier Ahmed Köprülü; in September of that same year, after being moved from different prisons around the capital to Adrianople (the imperial court's seat) for judgement on accusations of fomenting sedition, Sabbatai was given by Köprülü, in the name of the Sultan 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 Turkish 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. Some of his followers also converted to Islam—about 300 families who were known as the Dönmeh (converts) He was later banished twice by the Ottoman authorities who were tired of his schemes and discovered him singing psalms with the Jews. He later died in isolation.