Hessian War died out, and peaked after 1645 in the Hessian War proper. This open warfare began with the Siege of Marburg in 1645 and ended in April 1648 (but before the Treaty of Westphalia which was concluded later that year and ended the Thirty Years' War) with victory going to Hesse-Cassel. In the aftermath, Upper Hesse was divided and parts of its territory went to the now stronger Hesse-Cassel. At a European level the Hessian War must be viewed in the larger context of the Thirty Years' War, in which the reformed Hesse-Cassel sided with the Protestant Swedish party, whilst Hesse-Darmstadt,
Early modern period have] his religion") established the religious, political and geographic divisions of Christianity, and this was established in international law with the Treaty of Westphalia in 1648, which legally ended the concept of a single Christian hegemony, i.e. the "One, Holy, Catholic, and Apostolic Church" of the Nicene Creed. Each government determined the religion of their own state. Christians living in states where their denomination was "not" the established church were guaranteed the right to practice their faith in public during allotted hours and in private at their will. With the Treaty of Westphalia, the Wars of Religion came to an