In the ancient world, with regard to the status of an Emperor of the Roman Empire the legitimacy of authority was maintained by a successor keeping up the appearance of continuity by becoming the adopted child of the last Emperor; on rare occasions a blood relative succeeded by representation.
古くはローマ帝国の皇帝の地位は後継者が先代皇帝の養子となる体裁をもつことや、まれに実際の血族に代襲させることで権威の正当性を継続させていた。