Last Updated on February 13, 2023 by pg@petergamma.org
« Le roi est mort, vive le roi » is the heraldic formula with which the death of the old king was announced in France and at the same time the new one was proclaimed.
A herald is an official announcer or messenger, a person who announces important news.
https://en.wikipedia.org/wiki/The_king_is_dead,_long_live_the_king!