《左传·哀公·哀公十三年》
吴国人要带领哀公进见晋定公，子服景伯对使者说： 天子会合诸侯，那么诸侯之长就率领诸侯进见天子；诸侯之长会合诸侯，那么侯就率领子、男进见诸侯领袖。
吴人将以公见晋侯，子服景伯对使者曰： 王合诸侯，则伯帅侯牧以见于王。伯合诸侯，则侯帅子男以见于伯。
The men from Wu wanted to lead Duke Ai to see Duke Ding of Jin. Zifu Jingbo said to the messenger: If the emperor meets with the feudal lords, then the leader of the feudal lords leads the feudal lords to see the emperor; if the leader of the feudal lords meets with the feudal lords, then the marquis leads the viscount and baron to see the leader of the feudal lords.