At the end of the 11th century the government by a retired emperor in which a retired emperor who is the reign of the Imperial Family reigns as the real king (Chiten no kimi [the retired emperor in power]) began.
11世紀末になると天皇家の家督者たる太上天皇が実質的な国王（治天の君）として君臨し、政務に当たる院政が始まった。