King dead, king set is a popular saying in Portuguese, used in the political context when there is a immediate need to replace one ruler with another, without causing a great period of power vacancy.
There are several theories on how this expression came about, the most widely accepted being based on a classic story from Greek mythology.
According to the tale, the hero Theseus would have used this expression when he defeated the Minotaur (mystical creature, half bull and half man) and Minos, the king of Crete.
Immediately after defeating Minos and the monstrous creature, Theseus inherited the throne of Minos, the love of his widowed wife, and the worship of the people of Crete. Thus, the “dead king” of the famous popular saying would be a reference to Minos.
This legend is even narrated in the famous book “Rei Morto, Rei Posto” (The King Must Die, in the original title), by British writer Mary Renault (1905-1983).
Even though it is a more common expression in the political sphere, “king dead, king in place” can also be used in various contexts involving the replacement of someone in some position or function by another person.
Example: "The chief of staff was replaced this morning. King dead, king laid!”
In English, this expression can be translated to “the king is dead. Long live the king!" ("The king is dead. Long live the king!”), and is traditionally proclaimed when a new monarch rises to the throne.
This is a common phrase in countries like the UK and France (“Le roi est mort, live le roi!”, in the French translation).