Suleyman Shah
Ertuğrul or Ertuğrul Gazi (; ; died ) was the father of Osman I. Little is known about Ertuğrul's life. According to Ottoman tradition, he was the son of Suleyman Shah, the leader of the Kayı tribe (a claim which has come under criticism from many historians) of the Oghuz Turks, who fled from western Central Asia to Anatolia to escape the Mongol conquests, but he may instead have been the son of Gündüz Alp. According to this legend, after the death of his father, Ertuğrul and his followers entered the service of the Sultanate of Rum, for which he was rewarded with dominion over the town of Söğüt on the frontier with the Byzantine Empire. This set off the chain of events that would ultimately lead to the founding of the Ottoman Empire.