éminence grise

François Leclerc du Tremblay (right, in black robes) descending the staircase of the French Palais-Cardinal. Éminence Grise by Jean-Léon Gérôme (1873) An éminence grise ( French pronunciation: [eminɑ̃s ɡʁiz]) or gray eminence is a powerful decision-maker or advisor who operates covertly in a non-public or unofficial capacity.

The original French phrase referred to François Leclerc du Tremblay, the right-hand man of Cardinal Richelieu, the de facto ruler of France. Leclerc was a member of the Order of Friars Minor Capuchin and wore the gray-colored robe of that Franciscan order, which led them to use the familiar nickname the "Grayfriars" in the names of many Franciscan friaries throughout Medieval Europe. The color was less significant than its unmistakable contrast with the brilliant red worn by Richelieu as cardinal. The style "Your Eminence" or "His Eminence" is used to address or refer to a cardinal in the Catholic Church. Although Leclerc was never raised to the rank of cardinal, those around him addressed him as "eminence" as if he were one in deference to his close association with "His Eminence the Cardinal Richelieu".