Jeanne Sophie de Vignerot du Plessis

Septimanie d'Egmont or Jeanne Sophie de Vignerot du Plessis (Jeanne Louise Armande Élisabeth Sophie Septimanie; 1740 in Languedoc - 14 October 1773), was a French salonist.

Born as the daughter of Louis François Armand de Vignerot du Plessis, Duke of Richelieu, and Élisabeth Sophie de Lorraine (daughter of Joseph, Count of Harcourt), she was raised with her paternal aunt in a Benedictine convent and married in 1755 to Don Casimir Pignatelli, Count of Egmont.

She hosted a salon which gathered "the literary celebrities of the days" including Voltaire and Rousseau and was a center to the opposition of Madame du Barry. Through her close friendship with the Swedish ambassador to France, Ulrik Scheffer, she came to know the future Gustav III of Sweden during his visit to Paris in 1771 and continued a correspondence with him during his reign. She advised him to "repress the strife of the raging parties", advocated a "monarchy restrained by laws" and greeted his coup of 1772 with joy, especially its non bloody character. She called Gustav III "The hero of my heart", and it is considered likely that she had influence "upon the enlightened, humanistic, in many ways liberated direction of the early reign of Gustav III".

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