In 1106 Suk-jong’s son U, posthumous title Ye-jong, came to the throne. At the very first he was confronted by a new problem. The people had yet to learn that the coinage of money is a purely government monopoly. The readiness with which cash circulated tempted some to attempt to counterfeit it. The king consequently promulgated a law inflicting a heavy penalty upon this offense and at the same time made a law against the adulteration of food.
Having, in his third year, married a near relative he took as a teacher a monk named Un-jin, another indication of the steady progress of that cult. The talk about the change of site for the capital resulted in the building of a palace at P‘yŭng-yang and several royal progresses to each of the proposed sites.
The tribe of Yŭ-jin had repeatedly promised to remain peaceful and had as often broken their word; so now when they began to grow restless again, the king decided to make an end of the matter. He sent a strong force into their territory, killed 4,800 men and took several thousand prisoners. The territory was divided into four administrative districts.
In 1115 the king developed a fad. He became an enthusiastic botanist. He ransacked the kingdom for rare and beautiful plants and sent them to China in exchange for many kinds that were not indigenous.
We have now arrived at the threshold of events which were destined to result in the founding of a great dynasty. In order to explain we must go back a few years. Early in this dynasty a Koryŭ monk from P‘yŭng-yang, named Keum-jun, had fled, for some reason not stated, to the town of A-ji-go among the Yŭ-jin tribe. He had there married a Yŭ-jin woman and gotten a son whom he named Ko-eul. He in turn begot Whal-ra, and to him were born many sons, the eldest of whom was Hyo-ri-bal and the second Yong-ga. The latter was unusually bright and popular and eventually became chief; but on his death the son of his brother Hyo-ri-bal, named O-a-sok, took his place. O-a-sok died and his younger brother, A-gol-t‘a, became chief. Yŭ-jin was at this time a small weak tribe under the sway of the Ki-tan court, but now the masterly genius of A-gol-t‘a had come to her help, matters were destined to assume a different complexion.
It was now in 1114 that the little tribe of Yŭ-jin broke off its allegiance to Kitan and prepared to carve out a career for herself under her great leader. Soon an envoy came in haste from the capital of Kitan commanding the king to stand ready to drive back the Yŭ-jin tribe if they attempted to escape into his territory, for the emperor of Kitan was about to chastise his recalcitrant vassal.
The next year A-gol-t‘a with sublime presumption proclaimed himself emperor and named his kingdom Kin. At the same time he changed his own name to Min.
The Kitan emperor sent again demanding a contingent of Koryŭ troops. After anxious consultation it was decided to keep the soldiers near home and guard the interests of Koryŭ. In the war between Kitan and Kin the former were severely handled and again appealed to Koryŭ for help, but now with no hope of success.
The next year, 1116, a Koryŭ envoy Yun Eun-sun was sent to the Kitan court but he did not return, so a second one was dispatched to learn the cause. The fact is, the first envoy had fallen into the hands of a new power named Wŭn which had been set up in eastern Kitan by a man named Ko Yöng-ch‘ang. War was still raging between Kitan and Kin and the whole country was in a state of turmoil and confusion. The second envoy from Koryŭ fell into the hands of the Wŭn people but got out of the difficulty by promptly stating that he was accredited to them by the king of Koryŭ; and he forthwith laid out his present. This made the upstart “emperor” of Wŭn wild with delight and, loading the envoy with rich presents, he sent him back home. Instead of going back to the king, however, the envoy returned secretly to his own home, and it was only by accident that the king learned of his return. When he did learn of it he sent for the man and inflicted summary punishment. Of course the Wŭn people liberated the other envoy and sent him home. Him also the king punished for having saved his life by seemingly offering allegiance to Wŭn.
The emperor of China sent an envoy to Koryŭ with gifts of musical instruments and took advantage of the occasion to ask the Koryŭ king about the Kitan people. The king answered, “Of all the savage tribes they are the worst.” When this reply reached the Chinese court some of the courtiers said that the king of Koryŭ was trying to keep China from knowing Kitan, since there was treasure there which Koryŭ wanted to secure for herself. The emperor therefore sent and made an alliance with Kitan, which, as the sequel shows, cost him dear.