Emmanuel Armand de Vignerot du Plessis, Duke of Aiguillon (French pronunciation: [emanɥɛl aʁmɑ̃ də viɲʁo dy plɛsi]; 31 July 1720 – 1 September 1788), was a French soldier and statesman, and a nephew of Armand de Vignerot du Plessis, 3rd Duke of Richelieu.

This she did most effectively; letters of a very passionate nature were exchanged; the lady despatched those which she received to Richelieu, and in due course they were brought to the notice of Madame de La Tournelle, who, furious at the young duke's deceitfulness, turned her attentions to the king.

He was a member of the so-called parti devot, the faction opposed to Madame de Pompadour, to the Jansenists and to the parlement, and his hostility to the new ideas drew upon him the anger of the pamphleteers.

In 1753, he was appointed commandant (governor) of Brittany and soon became unpopular in that province, which had retained a large number of privileges called "liberties."

He would then lead his troops southwards, trapping the British defenders in a pincer between themselves and another French force that would land in southern England.

In 1768, the duke was forced to suppress this tribunal, and returned to court, where he resumed his intrigue with the parti devot and finally obtained the dismissal of the minister Choiseul (24 December 1770).

[1] When Louis XV, acting on the advice of Madame du Barry, reorganised the government with a view to suppressing the resistance of the parlements, d'Aiguillon was made Secretary of State for Foreign Affairs, with Maupeou and the Abbé Terray (1715–1778) also obtaining places in the ministry.

[1] D'Aiguillon, however, could do nothing to rehabilitate French diplomacy; he acquiesced in the first division of Poland, renewed the Family Compact, and, although a supporter of the Jesuits, sanctioned the suppression of the society.