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
Seventeen Provinces during the Eighty Years' War (see Generality Lands), which ended with the Treaty of Westphalia in 1648. Artois and parts of Flanders and Hainaut (French Flanders and French Hainaut) were ceded to France in the course of the 17th and 18th centuries. By the mid-16th century, the Margraviate of Antwerp (Duchy of Brabant) had become the economic, political, and cultural center of the Netherlands after its capital had shifted from the nearby Lordship of Mechelen to the city of Brussels. Bruges (County of Flanders) had already lost its prominent position as economic powerhouse of northern Europe. And Holland was gradually