The Chou dynasty in China had long been on the decline and now, in 305 B.C. had reached a point of extreme weakness. In view of this the governor of the tributary state of Liao-tung who had always passed under the title of Hu or “Marquis” dared to assume the title Wang or “King” and so to defy the power of China. Cho-sŭn threw herself into the balance in favor of her great patron and hastened to attack Liao-tung in the rear. But before this course had become inevitable a warning voice was raised and one of the councillors, Ye, who was gifted with more knowledge of the signs of the times than his fellows pointed out the inevitable overthrow of the Chou dynasty, and he advised that Cho-sŭn make her peace with the new “King” of the Yŏn kingdom of Liao-tung, rather than brave his anger by siding against him. The advice was followed and Cho-sŭn threw off the light reins of allegiance to China and ranged herself alongside the new kingdom. This we learn from the annals of the Wei dynasty of China. But apparently Cho-sŭn, stretching as it did to and beyond the Liao River, was too tempting a morsel for the ambitious king of Yŭn to leave untasted. So he picked a quarrel with the king of Cho-sŭn and delimited his territory as far as the Yalu River, a stretch of 2,000 _li_, even to the town of Pan-han whose identity is now lost. He followed up this success by overcoming the wild tribes to the north and added 1,000 _li_ more to his domains, securing it from attack, as he supposed, by building a wall from Cho-yang to Yang-p’yŭng. When Emperor Shih of the Tsin dynasty ascended the throne of China in 221 B.C. and soon after began that tremendous work the Great Wall of China, the fortieth descendant of Ki-ja was swaying the scepter of Cho-sŭn under the name Ki-bi, posthumous title Chong-t’ong Wang. As soon as the news of this great undertaking reached the ears of this monarch he hauled down his colors and surrendered at discretion, sending an envoy to do obeisance for him. King Ki-bi died and his son Ki-jun, the last of the dynasty reigned in his stead. For some years all was quiet, but at last the scepter was wrested from the hands of the short-lived Tsin dynasty by the founder of the illustrious Han, and across the border from Cho-sŭn all was turmoil and confusion. Fugitives from the three states of Yun, Che and Cho were seeking asylum anywhere, and thousands were hurrying across the Yalu and craving the protection of Ki-jun. The only protection he could give them from the victorious Han was remoteness from the latter’s base of operations; so he allowed them to settle along the valley of the Yalu and its southern tributaries. This was in the twentieth year of his reign, 200 B.C. Unfortunately for Cho-sŭn, the Han emperor made No-gwan, one of his generals, governor of Yŭn. This gentleman had ideas of his own, and finding such good material for an army among the half-wild people of his province he decided to go on an empire hunt on his own account.