Foundation of Yi Ja-gyeom's Political Power and Officializing Process of His Power in the Early Period of King Injong’s Reign

This article aimed at analyzing complex factors that made Yi Ja-gyeom in power and furthermore tried to find out how Goryeo reflected his unique authority in his position and officialized special power that originated from his authority. Yi Ja-gyeom was the first bureaucrat that was from non-royal family but alive as a grandfather of present king. In the same time, he was a meritorious retainer who enthroned his grandson King Injong by gathering support among aristocratic network members. His exceptional identities were formed by comprehensive combination of marriage rules of the Goryeo royal family, political situation after King Sukjong's accession, marriage strategies of the royal family in mid-Goryeo period, and biological coincidence. Hierarchy between King Injong and Yi Ja-gyeom differentiated according to the public and private spheres. Serious debate on legislative ways to accept their conflicting conditions was proceeded in the early period of King Injong’s reign and as a result the concept of ‘feudal lords with different family names (異姓諸王)’, which had already existed in chinese investiture system, was created in the Goryeo dynasty. Yi Ja-gyeom got the title as Joseongukgong (朝鮮國公), new rank higher than duke (公; gong) of the royal family. This concept and systematic foundation like arrangement of feudal administration office (開府) for it were used continuously until the period of Choi dictatorship. Yi Ja-gyeom went to the stage of referencing regent (知軍國事) as using the public foundation permitted to Joseongukgong. Unlike the case of Joseongukgong, this position of regent able to substitute for the monarchy could never be allowed in the Goryeo dynasty, and that’s why Yi Ja-gyeom failed in the end.