Westphalia to be Catholic. Osnabrück was divided almost equally between Catholicism and Protestantism. Parts of Westphalia came under Brandenburg-Prussian control during the 17th and 18th centuries, but most of it remained divided by duchies and other areas of feudal power. The Peace of Westphalia of 1648, signed in Münster and Osnabrück, ended the Thirty Years' War. The concept of nation-state sovereignty resulting from the treaty became known as "Westphalian sovereignty". After the defeat of the Prussian Army by the French at the Battle of Jena–Auerstedt, the Treaty of Tilsit in 1807 made the easternmost portion of today's Westphalia part of the
History of the Catholic Church in Germany for predominance in Europe. The war resulted in large areas of Germany being laid waste, a loss of approximately a third of its population, and in a general impoverishment. The war ended in 1648 with the Peace of Westphalia, signed in Münster and Osnabrück: Imperial territory was lost to France and Sweden and the Netherlands left the Holy Roman Empire after having de facto seceded 80 years earlier. The imperial power declined further as the states' rights were increased. "Aided by the personal charm of its young king Louis XIV, who had assumed the government in 1661, France appeared to