The Sung Emperor had abetted Aguta, and even urged him towards victory, hoping thus to regain the lands lying between the Yellow Sea and the Yellow River. The Kitans were crushed in the conflict, but the new power (the Kin dynasty) was more dangerous for him than the old, as he learned to his cost very quickly. In 1125 the Kin Emperor invaded North China; the year following he reached the Hoang Ho, or Yellow River, and besieged Kai fong fu which lies south of it. The Sung Emperor, who visited the camp of the invader to find peace there if possible, was seized and sent to Manchuria with his family. One of his brothers, living then in the South, was made sovereign by the Chinese. The Kins advanced farther, reached the Yang tse and took Lin ngan in the Che kiang province. They forced the Emperor to acknowledge their conquest and promise a yearly payment of twenty-five thousand pieces of silk with two hundred and fifty thousand ounces of silver, and to avow himself a vassal in addition. The rivers Hoai and Han formed the boundary between the two Empires, and now the Kin Empire reached a line almost half way between the great rivers Hoang Ho and Yang tse. The Sung Emperor moved his capital to Lin ngan, known as Han chau somewhat later. The Kins took up arms to extend their new Empire still farther southward, but were confronted by failure. The war ended in 1165 by a treaty which retained former boundaries, but decreased the Sung tribute. The southern Emperor, moreover, instead of being a vassal to him of the north, acquired the relation of a nephew to an uncle. But in 1206 the Sung Emperor began a new war which brought defeat to him. To restore peace he was forced now to pay the original tribute. About the middle of the 12th century the Kins had chosen the present Pekin as their residence; they called it Chong tu, or the middle capital. Lords over one third of China, they had adopted the customs and laws of that country. Their dominion extended on the north beyond China proper to Lake Baikal and the great Amoor River. The Kitans, once masters, had now become subjects to the Kin dynasty, but in 1162 they revolted; after that they were by force brought down to obedience. Some years before, the Kins had had a struggle with the Mongols which for the Kins proved disastrous. They ended it by making concessions. The Mongol chieftain then took the title of Khan, which he kept ever after. Jinghis, in beginning a war against China, was really attacking the Northern, or Kin dynasty, which had driven out that of the Kitans, hence, very naturally, he turned for co-operation to the Kitans. Madaku, the Kin Emperor, died in November 1209, and in 1210 an envoy informed Jinghis Khan that Chong hei, the eighth of the dynasty, had succeeded Madaku. The envoy demanded that the vassal, as he claimed to consider Jinghis, should receive the announcement while kneeling, in accordance with the etiquette of China. “Who is this new Emperor?” asked Jinghis of the envoy.