Öz
After the defeat of Kosedag, the Anatolian Seljuk State, which became the tributary of the Mongols, entered a process in which it started to lose its independence rapidly, with the sultanate struggles that started after the death of Sultan Kaykhusraw II. These sultanate fights, which were ignited by Guyuk Khan's declaration of prince Rukn al-Din Kilij Arslan as the sultan in 1249, turned into a regime struggle that left Anatolia in depression in a short time and after Sultan Izz al-Din Kaykaus II left the country in 1262 due to Mongol pressure, the Turkmens living in the border regions continued to resist the Mongols' hegemony in Anatolia. The Sultan Oyugi region, which is the subject of our study, also attracts attention during this period, as one of the places where anti-Mongolian opposition in Anatolia was most pronounced and the place where the foundations of the Ottoman Empire, which started a new era after the collapse of the Anatolian Seljuk State, were laid. In this article, the political conditions in which the Sultan Oyugi region during the Mongolian domination process were revealed mostly associated with the activities of Ertugrul Bey and his son Osman Bey.