Most sources agree that the Ottoman Turks belonged to the Kayı Oghuz Turkic clan, who, according to Ottoman traditions, fled their native homeland in Central Asia, during the early 13th century, due to the Mongol invasions. The clan settled in Anatolia, in a region belonging to the Seljuk Sultanate of Rûm. According to several sources, the Kayı warriors were known for filling first lines in battles, and their fighting skills and bravery were among the major factors the Seljuks were victorious in many battles. This fact prompted Sultan Kayqubad to appoint Ertuğrul, the clan's Emir, as a Moqaddam (Lieutenant), and to reward the Kayıs some fertile lands near Ankara, where they settled and remained in the service of the Sultan for several years. Later, Ertuğrul was granted dominion over the town of Söğüt in northwestern Anatolia on the Byzantine frontier. He started raiding the Byzantine possessions in the name of the Sultan successfully conquering several towns and villages, and slowly expanding his dominion during the half of the century he spent as a Seljuk governor. In 1281 CE, Ertuğrul passed away at nearly 90 years of age.