《左传·庄公·庄公二十三年》
诸侯朝聘天子，天子视察四方，以熟悉会见和朝觐的制度。
诸侯有王，王有巡守，以大习之。
The vassals go to court to pay their respects to the emperor, and the emperor inspects all directions to become familiar with the systems of meetings and audiences.