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
Battle of the Dunes (1658) The victory at the Battle of the Dunes and its consequences would lead to the end of ten years of war with the signing of Treaty of the Pyrenees. By this treaty France gained Roussillon and Perpignan, Montmédy and other parts of Luxembourg, Artois and towns in Flanders, including Arras, Béthune, Gravelines and Thionville, and a new border with Spain was fixed at the Pyrenees. The 1659 treaty also required the Spanish king to recognise and confirm all French gains in the 1648 Peace of Westphalia. The defeat of the Spanish relief force and the taking of Dunkirk ended the