Westphalia (German Westfalen), former Prussian province, now a part of the German state of North Rhine-Westphalia (Nordrhein-Westfalen). It was bounded by the Netherlands on the northwest, the former Prussian provinces of Hannover on the north and east, Hessen-Nassau on the southeast and south, and the Rhine Province on the southwest and west. The name Westphalian originally referred to one of the three divisions of the Saxon people. About 1180 Westphalia came under the archbishops of Cologne, as dukes of Westphalia. In 1807, combined with parts of Hessen, Hannover, Brunswick, and Saxony (Sachsen), Westphalia was made into a kingdom by Napoleon and given to his youngest brother, Jérôme Bonaparte; it was incorporated in the Confederation of the Rhine. In 1813, following Napoleon's military reverses, the kingdom was dissolved, and the Congress of Vienna assigned Westphalia to Prussia. The Peace of Westphalia, concluded at Münster and Osnabrück on October 24, 1648, brought the Thirty Years' War to an end.