The king is dead, long live the king!

"The King is dead, long live The King!" (French: Le roi est mort, vive le roi!;Spanish: El rey ha muerto, ¡viva el rey!; Italian: Il re è morto, lunga vita al re!; Portuguese: O rei está morto, longa vida ao rei!), or simply "long live the king!", is a traditional proclamation made following the accession of a new monarch in various countries. The seemingly contradictory phrase is used to simultaneously announce the death of the previous monarch and assure the public of continuity by saluting the new monarch.

In modern times, this phrase has become a popular phrasal template. Given the memorable nature of the phrase (owing to epanalepsis), as well as its historic significance, the phrase crops up regularly as a headline for articles, editorials, or advertisements on themes of succession or replacement. Robert Cecil, one of the architects of the League of Nations, famously concluded his speech at the final session of the League of Nations with the phrase: "The League is dead. Long live the United Nations."

The original phrase was translated from the French Le roi est mort, vive le roi!, which was first declared upon the accession to the French throne of Charles VII after the death of his father Charles VI in 1422. In France, the declaration was traditionally made by the duc d'Uzès, a senior peer of France, as soon as the coffin containing the remains of the previous king descended into the vault of Saint Denis Basilica. The phrase arose from the law of le mort saisit le vif—that the transfer of sovereignty occurs instantaneously upon the moment of death of the previous monarch. "The King is dead" is the announcement of a monarch who has just died. "Long live The King!" refers to the heir who immediately succeeds to a throne upon the death of the preceding monarch.

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Wikipedia