Osman I

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Osman I, also known as Osman Gazi (c. 1258 - c. 1323 CE), was the founder and first Sultan of the Ottoman Beylik, which would rise to eventually become the Ottoman Empire. He was the ruler of a small Turkic principality among many in the Anatolian region of Bithynia and, through a series of victories against the Byzantine Empire, would lay the foundation for his ancestors to build an empire spanning three continents, lasting centuries, and leaving its influence on the Middle East, Balkans, and the world.

More about: Osman I


  • c. 1258 - c. 1323
    Life of Osman I.
  • c. 1280
    Osman I succeeds his father Ertuğrul as ruler of his territory.
  • 1299 - 1326
    Reign of Osman I.
  • 1299
    Osman I’s forces lay siege to Nicaea.
  • 1300
    Osman I’s forces capture the city of Yenşiehir and make it the first capital of Osman’s Beylik.
  • 1301
    The Byzantine Empire breaks the siege of Nicaea.
  • 1302
    Osman I’s forces defeat the Byzantines at the Battle of Bapheus.
  • 1308
    The Bithynian capital of Prusa is put under siege by Osman I and his army.
  • c. 1323
    Osman I dies and his son Orhan succeeds him.
  • 1326
    Orhan successfully captures the city of Prusa, which he renames Bursa.