|Louis XV of France|
|Choisy le Roi|
At a masked ball on Shrove Tuesday 1742, Richelieu introduced Marie to the king, however at first Marie rejected the king's advances as she already had a lover and didn't want to give him up; the Duc d'Agenois. Jealous, the king sent the Duc d'Agenois to war in Italy against the Austrians, however he returned only wounded. Richelieu was Agenois' uncle, and so to help the king in his suit, had his nephew go to Languedoc, where he had arranged for a woman to seduce him. Agenois fell for the young woman and they exchanged passionate love letters; the young woman sent those she received to Richelieu who brought them to the attention of Marie. As a result, Marie was furious with her lover and so turned her attentions to the king. In return for becoming his mistress she demanded the king remove her elder sister, his official mistress, from court and give her the title and also granted Marie the title of Duchess of Chateauroux. Marie aided the court faction which brought France against Austria in the War of the Austrian Succession, and also persuaded the king to take the field himself in pursuit of military glory, and in June 1744 King Louis allowed Marie to join him with his army in the Austrian Netherlands. In August 1744 Louis fell critically ill while in Metz and under advisement from priests sent Marie away, however she soon returned to him when he recovered.