The Dönme (Dōnme, دونمه, Dönme) were a group of Sabbatean crypto-Jews in the Ottoman Empire who converted outwardly to Islam, but retained their Jewish faith and Kabbalistic beliefs in secret. The movement was centered mainly in Thessaloniki. It originated during and soon after the era of Sabbatai Zevi, a 17th-century Sephardic Jewish Rabbi and Kabbalist who claimed to be the Jewish Messiah and eventually feigned conversion to Islam under threat of death from the Sultan Mehmed IV. After Zevi's forced conversion to Islam, a number of Sabbatean Jews purportedly converted to Islam and became the Dönme. Some Sabbateans lived on into 21st-century Turkey as descendants of the Dönme. Today it is unclear how many people still call themselves Dönme although some still live in Teşvikiye in Istanbul. Most are buried in the Bülbüldere Cemetery (AKA Selanikliler Mezarlığı or the Cemetery of the Salonicans) in Üsküdar where, unusually, their gravestones feature photographs of the deceased. The Turkish word dönme (apostate) derives from the verbal root dön- (دون) that means "to turn", i.e., "to convert", but in the pejorative sense of "turncoat". The independent scholar Rıfat Bali defines the term dönme as follows: The term Donme is a Turkish gerund meaning 'to turn, revolve or return' and, by extension, "to betray" (i.e., 'go back on') and 'to convert' to another religion. It has come in popular parlance to refer to religious converts in general, and, more specifically, to the seventeenth century followers of the Jewish false messiah Sabbatai Sevi and their descendants, who outwardly converted to Islam but retained their secretive religious practices over the next several centuries, maintaining close communal and blood ties and practicing strict endogamy. While the great majority of the community's members abandoned their practices during the first quarter century, their past identity has continued to haunt them within Turkish society, and the term Dönme itself remains one of opprobrium.