Overview
Catherine Henriette de Balzac d'Entragues, Marquise de Verneuil (1579–1633) was the favourite mistress of Henry IV of France after Gabrielle d'Estrées died: her sister Marie-Charlotte de Balzac d’Entragues was also a mistress of the king. She was the daughter of Charles Balzac d'Entragues and his wife Marie Touchet, who was formerly the sole mistress of Charles IX of France.
Royal mistress
Catherine Henriette de Balzac was raised at a time when women often sought to become a royal mistress to royalty, and her mother Marie had previously been a mistress to Charles IX before her birth.
Ambitious, pretty and intriguing, by her late teens she had succeeded in becoming a mistress to Henry IV. While Henry was still deeply grieving over the death of Gabrielle d'Estrées, she induced him into a written promise to marry her. This led to bitter scenes of jealousy and arguing at the court when shortly afterwards Henry married Marie de' Medici instead.
Terribly infuriated and feeling betrayed, she carried her spite so far as to be deeply compromised in a conspiracy against the king in 1608, but escaped with only a slight punishment after the plot was foiled, and in 1608 Henry took her back into favour again as one of his mistresses.
From Wikipedia (CC BY-SA 4.0).