a legitimated prince of France (of royal descent) and peer of France, was a major figure in the civil war of France, the Fronde, and served as governor of Picardy, then of Normandy. Longueville headed the French delegation in the talks that led to the Treaty of Westphalia which ended the Thirty Years War (1648). In his role as sovereign prince of Neuchâtel, and acting as antagonist of the Habsburg power rather than as liberal benefactor, he succeeded in obtaining formal exemption from the Holy Roman Empire for all cantons and associates of the Swiss Confederacy.
