Ertugrul (Ottoman Turkish: ???????, Turkish: Ertugrul Gazi, Er?ogril; often with the title Gazi) (died c.
1280) was the father of Osman I.
According to Ottoman tradition, he was the son of either Günduz Alp or Suleyman Shah, leader of the Kayi tribe of Oghuz Turks, who fled from western Central Asia to Anatolia to escape the Mongol conquests.
According to this legend, after the death of his father, Ertugrul and his followers entered the service of the Seljuks of Rum, for which he was rewarded with dominion over the town of Sögüt 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.
Like his son, Osman, and their descendants, Ertugrul is often referred to as a Ghazi, a heroic champion fighter for the cause of Islam.