Peace of Westphalia

The series of treaties signed at Münster and Osnabrück in October 1648 ended the Thirty Years' War in the Empire and the Eighty Years' War between Spain and the Dutch Republic. The settlement recognized the sovereignty of the German princes, granted formal independence to the Dutch and the Swiss, and established the principle of cuius regio, eius religio (whose realm, his religion) on a durable basis. Conventionally cited as the foundation of the modern European state system.