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
Treaty of the Pyrenees princess entered France. In addition, the English received Dunkirk, although they elected to sell it to France in 1662. The Treaty of the Pyrenees was the last major diplomatic achievement by Cardinal Mazarin. Combined with the Peace of Westphalia, it allowed Louis XIV remarkable stability and diplomatic advantage by means of a weakened Louis II de Bourbon, Prince de Condé and a weakened Spanish Crown, along with the agreed dowry, which was an important element in the French king's strategy: All in all, by 1660, when the Swedish occupation of Poland was over, most of the European continent was at