Since the founding of Goryeo, King Taejo (Wang Geon) vigorously pushed forward with the policy of northern expansion in an aspiration to regain the former territories of Goguryeo. He named the state ‘Goryeo’as a means of succeeding Goguryeo. He called Pyongyang, the capital of Goguryeo‘, Seogyeong’ and established the city as the base for his northern expansion policy. King Taejo accepted the powerful local gentry leaders as the central aristocracy while entrusting the lesser castle lords to rule over the countryside.
It was during the reign of King Gwangjong, the fourth monarch of Goryeo, that the nation’s royal authority became firm and the centralized governance system took root. King Gwangjong launched an investigation into those who had been illegally forced into slavery by the local gentry during the chaotic period of the Later Three Kingdoms. Those who had originally been commoners were restored to free status. King Gwangjong adopted the civil service examination of China to appoint men of learning to government posts.
These reforms brought down the foundation of the local gentry and eventually served to strengthen royal authority. The ruling system of the nation was established during the reign of King Seongjong. King Seongjong dispatched officials from the central government to head provincial administrative units that had previously been under the supervision of the local gentry. To control the local gentry, they were incorporated into the ‘Hyangni’(country functionary system). The central political structure was remodeled to fit the circumstances of Goryeo. Efforts were exerted in the education of Confucianism, and ‘Gukjagam’, the national institute of higher learning, was established during this period. The regional administrative unit of Goryeo was largely divided into Gyeonggi1), five provinces called ‘do’, two border regions called gye’, under which were ‘gun’districts and ‘hyeon’counties. However, officials could not be dispatched to all ‘gun’or‘ hyeon’areas. In these areas where officials were not dispatched, functionaries of the region were entrusted with the practical administrative affairs. Also, the ‘so’were established in various parts of the nation, which were in charge of producing various resources needed by the government offices or daily necessities such as gold, silver, metal, porcelain, paper, ink sticks and salt.