Claude de Mesmes, comte d'Avaux (like Rafał Leszczyński). Count d'Avaux concluded treaties between France and Sweden in 1638 and 1641, and during the years 1643–1648, he took part in the lengthy negotiations which led to the Peace of Westphalia, which ended the Thirty Years' War. However, d'Avaux was removed from the Congress of Westphalia in 1648, largely due to ideological differences and competition with the other French diplomats and with his superiors in France. Although this affair damaged his reputation, he ended his life serving the French government as a member of the high Council of the Realm. Claude de Mesmes, comte d'Avaux Claude de
Treaty of the Pyrenees Spanish Habsburg victories in the Dutch Revolt in the 1620s and at the Battle of Nördlingen against Sweden in 1634. By 1640, France began to interfere in Spanish politics, aiding the revolt in Catalonia, while Spain responded by aiding the Fronde revolt in France in 1648. During the negotiations for the Peace of Westphalia in 1648, France gained the Sundgau and cut off Spanish access to the Netherlands from Austria, leading to open warfare between the French and Spanish. After 23 years of war, an Anglo-French alliance was victorious at the Battle of the Dunes in June 14, 1658, but