Anne de Richelieu was born in 1622 and spent the majority of her life at court of either Louis XIII or Louis XIV. She was the daughter of François Poussard du Vigean, Baron de Fors and Anne de Neufbourg.
She was first married to François-Alexandre d'Albret, Comte de Marennes on 16 October 1644. However, her husband died after a few years of marriage which left Anne once again on the marriage market. Her father was quick to arrange for a new match for her - and a very advantageous one at that. In 1649, Anne was married to the Duc de Richelieu.
The marriage was considered to be somewhat of a mystery. Anne was particularly young nor did she have a fortune. Her father's title was not very grand and Anne herself was not considered to be beautiful. As Madame de Caylus put it, the match was to "the astonishment of the whole court".
Anne's years as a Duchesse earned her a position of privilege. On 21 November 1671, she was given her own official position at court when she was made Premier dame d'honneur to Marie-Thérèse. Prior to this, she had lived primarily at the Hôtel de Richlieu in Paris which is now destroyed. It was while she served the queen, that she made a new friend: Madame de Montespan. Despite being employed by the spouse of Madame de Montespan's lover, the two got on quite well. As it happens, Anne used her position near the queen to ease the relationship between La Montespan and Marie Thérèse.
As Madame de Montespan's reign progressed, the royal favourite would learn that her friendship with Anne de Richelieu was truly valuable. In 1675, Madame de Montespan and Louis XIV's relationship was interrupted and the two became temporarily estranged. While Madame de Montespan was absent from court, Anne worked behind the scenes and arranged for a meeting between the queen and La Montespan. The result was that the two were reconciled. Both Madame de Montespan and Louis XIV were well aware of the involvement of Anne and both remained grateful to her.
Meanwhile, in her own marriage, Anne encountered somewhat different troubles. Her husband, Armand Jean de Vignerot du Plessis, had his own established mistress in Françoise de Dreux. Such arrangements were far from uncommon but this particular one almost turned fatal. Françoise de Dreux dabbled in some sinister occult practices and apparently came to consider Anne to be in her way. Françoise attempted to poison Anne but failed. Françoise would later be convicted of the attempted murder as well as several successful ones in 1679.
Anne would never have children of her own. Neither of her marriages produced any known offspring and she does not appear to have had any affairs.
Marie Thérèse died in 1683 which meant that Anne was without official employ. However, likely due to her favour with the king, she was transferred to the service of the Grande Dauphine. Here she made a new friend who would come to serve the same capacity as Madame de Montespan had: Madame de Maintenon. Apparently, Anne had a habit of making fast friends with the king's mistresses but without sacrificing her own position. Unfortunately for Anne, she would not live to reap the rewards of being the friend of Madame de Maintenon. Anne died on 28 May 1684 in Paris.