Margraviate of Brandenburg fief of the Polish–Lithuanian Commonwealth, to which the electors paid homage. The electors of Brandenburg spent the next two centuries attempting to gain lands to unite their separate territories (the Mark Brandenburg, the territories in the Rhineland and Westphalia, and Ducal Prussia) to form one geographically contiguous domain. In the Peace of Westphalia ending the Thirty Years' War in 1648, Brandenburg-Prussia acquired Farther Pomerania and made it the Province of Pomerania by the Treaty of Stettin (1653). In the second half of the 17th century, Frederick William, the "Great Elector", developed Brandenburg-Prussia into a major power. The state constructed Brandenburg's
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