Prisoner of war the custody of a person, then the responsibility was on the individual. The freeing of prisoners was highly recommended as a charitable act. The 1648 Peace of Westphalia, which ended the Thirty Years' War, established the rule that prisoners of war should be released without ransom at the end of hostilities and that they should be allowed to return to their homelands. There also evolved the right of "parole", French for "discourse", in which a captured officer surrendered his sword and gave his word as a gentleman in exchange for privileges. If he swore not to escape, he could gain
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