Elizabeth Charlotte, Countess Palatine of Simmern (1652-1722 at the Chateau de Saint-Cloud near Paris), known in French as la princesse palatine and in German as Liselotte von der Pfalz, was a princess of the electoral family of the Palatinate who became Duchess of Orleans by her marriage to Philip I, Duke of Orleans, younger brother of Louis XIV of France, and then in 1693 by inheritance Duchess of Montpensier in her own right. When the Wittelsbach branch of Palatinate-Simmern became extinct in the male line with the death of her brother Karl II, Elector Palatine in 1685, her brother-inlaw Louis XIV claimed the Palatinate and started the War of the Palatine Succession (1688 - 1697). Her brothers death also meant that she became the heiress of the then Duchess of Montpensier, her distant childless cousin and her husbands first cousin. After the deaths of her husband in 1701 and of Louis XIV in 1715, her son-Philip II, Duke of Orleans-became Regent of France (1715-1723), acting for the underage king Louis XV of France.