Éminence grise

An éminence grise (French pronunciation: ​[eminɑ̃s ɡʁiz]; English: grey eminence) is a powerful decision-maker or adviser who operates "behind the scenes" or in a non-public or unofficial capacity.

This phrase originally referred to François Leclerc du Tremblay, the right-hand man of Cardinal Richelieu. Leclerc was a Capuchin friar who was renowned for his beige robe attire, as beige was termed "grey" in that era. The title His Eminence is used to address or refer to a Cardinal in the Roman Catholic Church. Although Leclerc never achieved the rank of Cardinal, those around him addressed him as such in deference to the considerable influence this "grey" friar held over "His Eminence the Cardinal".

Leclerc is popularly referred to in several works. Aldous Huxley wrote an English biography of Leclerc entitled Grey Eminence. There is also an 1873 painting by Jean-Léon Gérôme, L'Éminence Grise, which depicts him descending the grand staircase of the Palais Cardinal. Leclerc is referred to in Alexandre Dumas' The Three Musketeers as the character Father Joseph, a powerful associate of Richelieu and one to be feared.

The character Marquis de Carabas has this role in the novel and television series, Neverwhere.

In the game, Crusader Kings II, the "Grey Eminence" trait grants a character a high bonus for diplomatic ability.

In season 4 of the U.S. version of House of Cards, First Lady Claire Underwood becomes the éminence grise behind Acting President Donald Blythe when President Underwood is hospitalized after an assassination attempt.

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