 The group originated during and soon after the era of Sabbatai Zevi, a 17th-century Jewish rabbi and kabbalist who claimed to be the Jewish Messiah and eventually converted to Islam under threat of death penalty by the Sultan Mehmed IV.After Zevi's conversion, a number of Jews also falsely converted to Islam and became the Dönmeh.Since the 20th century, assimilated Dönmeh have intermarried with other groups and most have assimilated into Turkish society.