Ertugrul or Ertugrul Gazi was the father of Osman I. Little is known about Ertugrul's life. According to Ottoman tradition, he was the son of Suleyman Shah, the leader of the Kayı tribe 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 Gunduz Alp. https://www.vidzmine.com/@TRTErtugrul