Franco-Dutch War of the Dutch Republic by surprise, is often referred to as "het Rampjaar" ("the Disaster Year") in Dutch. In order to weaken its Hapsburg rivals in Spain and the Holy Roman Empire, largely Catholic France supported the Dutch Republic during the 1568-1648 Eighty Years War and in 1635, it entered the Thirty Years' War as part of the anti-Imperial Protestant alliance. The 1648 Peace of Westphalia ended the wider war but the subsidiary Franco-Spanish War continued until the 1659 Treaty of the Pyrenees; the net effect was that Spain was no longer the dominant power in Europe, while France emerged
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