The maternal relatives of the King in Koryeo dynasty basically had a character to protect royal families. Their status and roles became bigger as the royal family except kings and crown princes didn’t take on state affair. Some of them were not the royal family, in that case they could participate in governmental affairs in a government position. The maternal relatives of the King supported the related person when there was a conflict of the succession to the throne, but they rarely struggled for power with royal family itself. There was a rule that the first son of the king succeeded to the throne. In case the king had no sons or had only young sons, the younger brother of the king succeeded to the throne. When the young prince succeeded to the throne, his uncle happened to stage a coup. The younger the king was, the more powerful his maternal relatives were. When maternal relatives became strong so that they could press the royal authority, they came into conflict with the king. Rarely had maternal relatives the power enough to threaten the royal authority or monopolize the political situation during the early days of the Koryeo Dynasty. In addition to maternal relatives, various political forces existed during the Koryeo Dynasty. If we overemphasize on the impact of the maternal relatives, we can distort the flow of political situation. The king and bureaucrats as a male ruled Koryeo, but the Empress Dowager and the queen with their family sometimes went into the frontline of politics.