Nothing is known with certainty about Ertuğrul's life, except that he existed and was the father of Osman, the first ruler of what was to become the Ottoman Empire. Historians are thus forced to rely upon stories written about him by the Ottomans more than a century later, which are of questionable accuracy.[2] According to these later traditions, Ertuğrul was chief of the Kayı tribe[5] of Oghuz Turks, as a result of his assistance to the Seljuks against the Byzantines. Ertuğrul was granted lands in Karaca Dağ, a mountainous area near Angora (now Ankara), by Ala ad-Din Kay Qubadh I, the Seljuk Sultan of Rûm. 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.[6] Later, he received the village of Söğüt which he conquered together with the surrounding lands. That village, where he later died, became the Ottoman capital under his son Osman I. Ertuğrul had two other sons, Saru Batu Savcı Bey and Gündüz Bey.
