Upon the death of King Louis XV's mistress, Madame de Vintimille, in childbirth in 1741, the king's best friend (and the duc d'Agénois' uncle), the manipulative Duke of Richelieu, began to cast about for another candidate to fulfil his royal friend's desires, as he did not want Madame de Vintimille's older sister, Madame de Mailly, to regain the king's affections. He eventually decided upon the younger sister of both Madame de Mailly and Madame de Vintimille, Marie Anne, the widow of the marquis de La Tournelle.