During the latter half of the 14th century, the power of the Yuan deteriorated and the Ming emerged as the new ruler of China. Rebellious forces of the Chinese Han rose throughout China and spread across the nation. King Gongmin, who came to the throne during this period, formulated strong reformative polices in order to overcome the Yuan domination by taking advantage of the chaotic circumstances in China. King Gongmin got rid of the instruments of the Yuan that intervened in the internal affairs of Goryeo, recovered the territories in Hamgyeong-do province that had been taken by the Yuan, and even went as far as to attack the Liaotung region to regain the ancient territories of Goguryeo. He also reinstated the diverse systems that had been revised under the Yuan and banned the customs of the Mongols. Meanwhile, he ousted all those who traced their power to the Yuan Dynasty. King Gongmin appointed Sin Don, a monk, to carry out these sweeping reform plans. Sin Don returned land that had been illegally seized by the‘ powerful families’(the aristocratic families who had control over power and the economy for a long time) to the peasants who had been the original owners, and freed the slaves of the powerful families, who had originally been peasants. King Gongmin’s reforms, however, were met with strong resistance. There lacked a solid base of support and the opposition from the conservatives was quite intense. Objecting to King Gongmin’s reforms, the members of the powerful families had Sin Don executed on charges of treason and King Gongmin himself met a mysterious death. The reforms pursued by King Gongmin thus ended in failure.