Osman Ghazi ben Ertuğrul ( Osman Ghazi; or Osman Bey or Osman Alp); (1258–1326), sometimes transliterated in the past as Othman or Ottoman or Atman (from the contemporary Byzantine Greek version of his name, Άτμαν) and nicknamed "Kara" ( "dark" in Turkish), was the leader of the Ottoman Turks and the founder and namesake of the dynasty that established and ruled the Ottoman Empire. The state, while only a small principality (beylik) during Osman's lifetime, would prevail as a world empire under Osman's dynasty for the next six centuries after his death. It existed until the abolition of the sultanate in 1922, or alternatively the proclamation of the Republic of Turkey in 1923, or the abolition of the caliphate in 1924.