Very few women in history have betrayed their sisters to become the king's mistress. Maybe that's why Marie Anne de Mailly, arguably history's worst sister, is so intriguing.
Hortense Mancini: The Duchess Who Ran Away
Hortense Mancini was quite an interesting lady. She had a husband who knocked out female servants’ front teeth, she ran away from him, and became a royal mistress.