Osman I

Osman I or Osman Ghazi (died 1323/4), sometimes transliterated archaically as Othman, was the leader of the Kayi tribe and the founder of the Ottoman dynasty. The dynasty bearing his name later established and ruled the Ottoman Empire (first known as the Ottoman Beylik or Emirate). This state, while initially a small Turkmen principality during Osman's lifetime, transformed into a world empire in the centuries after his death. It existed until shortly after the end of World War I.