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
Hessian War Peace Congress mediated by Duke Ernest of Saxe-Gotha and which resulted in a unification and peace treaty that was sealed in April 1648, ahead of the Treaty of Westphalia itself. Before the Westphalian Peace Treaty, Cassel fought one last time against the imperial side, winning the Battle of Wevelinghoven in the Rhineland, together with other Protestant troops. Darmstadt, however, was not involved in this battle. Under the Unification Treaty between Cassel and Darmstadt, Upper Hesse was permanently divided. Darmstadt had to give up a significant part of Upper Hesse to Cassel, not least Marburg and other occupied territories, including the