In 1478 the queen died and a concubine named Yun was raised to the position of royal consort. This was destined to bring dire disaster to the realm. She was a woman of jealous disposition and violent temper and her hatred of the other concubines led her into trouble. On one occasion her passions overcame her and in an angry altercation with the king she scratched his face severely. The king desired to treat her offense leniently but he was overruled by the officials and the woman was driven from the palace. She had one son who is commonly known by his posthumous title Prince Yŭn-san. When the disgraced woman was dying she charged this son to avenge her disgrace, when he should come to the throne; for he was the heir apparent. The reign saw many reforms of a social character. It was decreed that grave-plots must not be allowed to interfere with the making of fields. This indicates that during the years of prosperity the population had been rapidly increasing and that it was found necessary to increase the area of arable land in like proportion. The people were reaping the reward of many years of peace and good government. Nothing could show more plainly the relation between King Sŭng-jong and the people than the custom he inaugurated of helping those to marry who were too poor to do so. The only books he caused to be published were four; on marriage, funerals, ancestor worship and “On Reaching Manhood.” He seems to have been an ardent Confucianist for among other things he ordered that widows should not be allowed to re-marry. This striking feature of Korean life dates from the days of this king. Before this there had been a certain amount of sentiment against the practice but it had been common even among ladies of the higher classes up to this time. His refusal to give books to the Japanese envoys would also lead us to believe that he was an active Confucianist. All these years we hear of no dealings with China on the part of Cho-sŭn, but at this point we are told that the wild tribe of Yŭ-jin was harrassing the people of northern China and the Emperor sent a message to Korea calling upon her to combine with China in an attack upon this obnoxious tribe. The military policy of his predecessors now stood the King in good stead, for he was able to put a strong army in the field immediately and the tribe of Yŭ-jin was speedily chastised. The Emperor was highly pleased and sent the King a present of silk, gold thread and cotton cloth. In the latter years of his reign the King had the Kuk-cho Po-gam written up to date, and he successfully withstood an invasion of the wild tribes of the north. One of his last acts was to order that all impurity and obscenity should be dropped from the songs and poems.