Osman Gazi ben Ertuğrul (Ottoman Turkish: عثمان غازى‎ Osman Ghazi; or Osman Bey or Osman Gazi Han); (1258–1326), sometimes transliterated in the past as Othman or Ottoman or Ataman and nicknamed "Kara" ("black" in Turkish), was the leader of the Ottoman Turks and the founder and namesake of the dynasty that established and ruled the Ottoman Empire.