The Turks who lived in Turkistan and territories lying to the north of China arrived in the tenth century and settled down in Persia and Asia Minor, together with some allied or subject races, such as the Tatars. There they founded several dynasties. Out of the numerous branches of the Turkish race we will only deal with the Ottomans, who were to establish their rule in Asia Minor and Europe. People too often forget the wonderful rise of the Turkish Empire, which for nearly three centuries increased its power and enlarged its territories; and they lay too much stress on its decline, which began two centuries and a half ago. The Oghouz tribe of Kaï, following the Seljuks more or less closely in their migrations, reached the uplands of Asia Minor about the end of the tenth century. While part of the latter retraced their steps towards the territories from which they had started, the others settled down and founded the Empire of Rum. The Seljukian chief, Ala Eddin Kaï Kobad I, gave to Erthoghrul, a son of Suleiman Khan, the ancestor of the Seljukian dynasty of Konia, the summer pasturage of Mount Toumanitch, south of Brusa, on the boundaries of the Roman Empire of Byzantium. Erthoghrul and his successors strengthened and enlarged their dominions and laid the foundation of Ottoman power. Othman, or Osman, settled at Karahissar about the end of the thirteenth century, at the time when the Seljukian Empire of Rum was destroyed by Mongol inroads, and he conquered several of its principalities.