In seventeenth-century France, aristocratic women were valued by their families as commodities to be married off in exchange for money, social advantage, or military alliance. Once married, they became legally subservient to their husbands. The duchesse de Montpensier-a first cousin of Louis XIV-was one of very few exceptions, thanks to the vast wealth she inherited from her mother, who died shortly after Montpensier was born. She was also one of...