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
Kettle War the economy of the northern Netherlands (namely Amsterdam), but the southern cities were dislodged from their important trading position. The closure of the Scheldt was confirmed by the Peace of Westphalia in 1648, to which the Spanish agreed. After the War of the Spanish Succession, the Spanish Netherlands had been ceded to Austria by the Treaty of Rastatt in 1714. Since Europe's "Diplomatic Revolution" of 1756, Austria, and thus the Austrian Netherlands, had been in an alliance with France. Prussia, France's former ally, entered into an alliance with Britain. The change, sensational at the time, made nonsense of all the