During 1209 the Mongol sovereign returned home in triumph and found Arslan Khan of the Karluks and the Idikut of the Uigurs waiting to render him homage. Arslan Khan had till then ruled conjointly with an agent of the Gurkhan, his suzerain. But, as the power of the Gurkhan had diminished in recent days very sensibly, many princes, who had recognized him up to that time, revolted. Among these was the Sultan of Khotan, who marched against him with an army, and persuaded Arslan Khan to drop allegiance. Arslan made haste to help the Sultan all the more, since at that time he was advised of the Gurkhan’s plans by that sovereign’s deceitful Emir, Tanigu. This traitor so represented Arslan to his overlord, the Gurkhan, that the latter gave him the title “son,” and appointed for him the agent whom Tanigu recommended. But when Mongol victories sent panic throughout Northern Asia, Arslan acted quickly. He slew the agent of the Gurkhan, joined Jinghis Khan very promptly, and waited for his favor. Arslan said that if he received a golden girdle, and a high position in the Mongol service he would have one wish alone ungratified: to be the fifth son of the great Khan. Jinghis, divining this wish of his, or learning of it, had it gratified. He gave Arslan his daughter, Altun Bighi, in marriage, and with her the title of fifth son was added. Thus Jinghis Khan was intrenched in Kara Kitai very firmly. His next move was on Kitai itself, the great North China Empire. He was now master of mighty legions drawn from all tribes whose leaders and chiefs he had driven from existence in that fierce fight for dominion, during which no mercy had been manifest on either side, but in which greater wisdom, with keenness and skill, also fortune to some extent, were with Jinghis. CHAPTER V JINGHIS KHAN’S TRIUMPHANT ADVANCE BEYOND THE GREAT WALL OF CHINA Many provinces of China had been subject to foreign rule for three centuries. After the fall of the Tang dynasty, which had ruled the whole country from 618 to 907, this immense Empire fell to commanders of provinces and was cut up into ten states co-existent and separate. Intestine wars, the result of this parceling, favored the rise of a new power in Northern Asia. The Kitans, who formed a part of the Manchu stock, held that country from the Sungari southward as far as the present Shan hai kuan, and from the Khingan range on the west to Corea. These people had for a long time been vassals of Tartar Khans, and next of Chinese Emperors. They were divided into eight tribes, each with its own chief or manager. Abaki, the head of the Sheliyu tribe, which owned the district known at the present as Parin, gained supreme power in 907, and used the whole strength of the Kitans to subdue Northern Asia. In 916, he proclaimed himself sovereign, and when he died, ten years later, his dominion extended eastward to the ocean, and westward to the Golden Mountains or to the Altai.