To this outward danger was added the terror of civil strife for the priests took this inopportune moment to attack the old general, Ch‘oe, who still ruled with a high hand. He turned on them however and cut down three hundred. He then instituted an inquisition and as a result 800 more were killed.
Such then was the desperate position of Koryŭ; a powerful enemy at her door, the south rife with rebellion, and in the capital itself “mountains of dead and rivers of blood.” Victorious Kitan came sweeping down on Song-do, but for some reason, perhaps because they had heard that the town was well defended, they made a detour, appearing next on the banks of the Im-jin River half way between Song-do and the present capital. There they suffered defeat at the hands of the Koryŭ forces as they did also later at the site of the present capital. In view of these defeats the Kitan army retired to Tă-băk San. Now another cause of anxiety appeared in the shape of the Yŭ-jin allies of the Mongols who crossed the Yalu and took Eui-ju. But Koryŭ, wide awake to the danger, threw upon them a well equipped force which destroyed 500 of them, captured many more and drove the remaining 300 across the river. The king now built a royal residence at Pă-gak San to the east of Song-do, for he had been told that by so doing he would be able to hold the north in check.
Myŭn Ku-ha of east Yŭ-jin, being defeated by the Mongols, came in his flight towards the Yalu, but the Koryŭ general, Chŭng Kong-su, caught him and sent him safely to the Mongol headquarters. This pleased the Mongols hugely and they said “We must make a treaty of friendship.” We must remember that the Mongols were at war with Kitan and had driven her army across into Koryŭ, but at first did not pursue them. Now, however, an army of 10,000 men under Generals T‘ap Chin and Ch‘al Cha, were sent to complete the destruction of the Kitan power. They were joined by Yŭ-jin allies to the number of 20,000 men under Gen. Wan-an Cha-yŭn. As these allies were advancing against the doomed army of Kitan, the remnant of which, 50,000 strong, was massed at Kang-dong, a great snowstorm came on and provisions ran low. Koryŭ was asked to supply the deficiency which she did to the extent of 1,000 bags of rice. This still more helped her into the good graces of the Mongols. But the records state that the Mongols were so little beyond the condition of the savage that there could be little real friendship between them and the people of Koryŭ. The latter showed it too plainly and the Mongols of course resented it.