|Leader of the Kayı tribe (pre-Ottoman Empire)|
|Full name||Ertuğrul Gazi|
|Born||1191 / 1198
|Died||1281 (aged 83-90)
Ertuğrul (Ottoman Turkish: ارطغرل, often with the title Gazi) (1191 / 1198 – 1281) was the father of Osman I, the founder of the Ottoman Empire. He was the leader of the Kayı clan of the Oghuz Turks. When arriving in Anatolia from Merv (Turkmenistan) with his 400 horsemen to aid the Seljuks of Rum against the Byzantines, Ertuğrul set off the chain of events that would ultimately lead to the founding of the Ottoman Empire. Like his son, Osman, and his future descendants, Ertuğrul is often referred to as a Ghazi, a heroic champion fighter for the cause of Islam.
Ertuğrul was born in Ahlat. In 1230, he inherited the command of the Kayı tribe of the Oghuz Turks as a result of his assistance to the Seljuks against the Byzantines. Ertuğrul received lands of Karaca Dağ, a mountainous area near Angora (now Ankara), by Ala ad-Din Kay Qubadh I, the Seljuk Sultan of Rum. One account indicates that the Seljuk leader's rationale for granting Ertuğrul land was for Ertuğrul to repel any hostile incursion from the Byzantines or other adversary. Later, he received the village of Söğüt which he conquered in 1231 together with the surrounding lands. That village, where he later died, became the Ottoman capital in 1299 under Osman I, Ertuğrul's son. Ertuğrul had two other sons, Saru Batu Savcı Bey and Gündüz Bey.
See also 
- History of the Ottoman Empire and modern Turkey, Volume 1, By Stanford Jay Shaw, Ezel Kural Shaw, pg. 13
- Southeastern Europe under Ottoman rule, 1354-1804, By Peter F. Sugar, pg.14
- The Ghazi Sultans and the Frontiers of Islam, By Ali Anooshahr, pg. 157
- Biography of Ertuğrul Retrieved on 2008-07-23.