Baroness Emmuska Orczy 
Petticoat Rule 

This novel is called "Petticoat Rule" because during the 1740s in France there were notable females influencing their male contemporaries. Lydie d’Aumont, who is the main focus of this fiction based on fact, is daughter of the French prime minister. Therefore, whoever marries her will gain power, as the prime minister is easily persuaded by his daughter to do what she wants. As for the story, one main theme revolves around the "pretender" to the English throne, Charles Edward Stuart, and how he is originally welcomed to the French court, only to be betrayed by Louis XV, Madame de Pompadour, and their devotees; however, Lydie and her husband have other ideas and risk their favour with the king by trying to warn Bonnie Prince Charlie that the French plan to hand him over to the English if possible. (Goodreads)