Ertuğrul, also known as Ertuğrul Ghazi, was a 13th-century uch bey (marcher-lord) in Anatolia. He is historically significant as the father of Osman I and a foundational figure in the origins of the Ottoman Empire. While specific details regarding his life are scarce, he is traditionally recognized for leading followers into the service of the Sultanate of Rum.
According to Ottoman tradition, Ertuğrul was the son of Suleyman Shah, the leader of the Kayı tribe of the Oghuz Turks who migrated from western Central Asia to Anatolia to escape Mongol conquests. However, contemporary numismatic evidence suggests he may have been the son of Gündüz Alp. Following his father's death, Ertuğrul was rewarded with dominion over the town of Söğüt on the frontier with the Byzantine Empire, an event that initiated the sequence of occurrences leading to the establishment of the Ottoman state.