Sayyid (also spelled "Seyd", "Syed", "Sayed", "Sayyed", "Saiyid", "Seyed" and "Seyyed") (, or , ; meaning Mister) (plural Sadah , ) is an honorific title denoting males accepted as descendants of the Islamic Prophet Muhammad through his grandsons, Hasan ibn Ali and Husayn ibn Ali, sons of Muhammad's daughter Fatimah and his son-in-law Ali (Ali ibn Abi Talib). Conventionally, descent is patrilineal. However, in 1632 when an Ottoman court challenged a man wearing a sayyid's green turban he established that he was a sayyid on his mother's side, and this was accepted by the court.