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
Peace of Westphalia Peace of Westphalia The Peace of Westphalia () was a series of peace treaties signed between May and October 1648 in the Westphalian cities of Osnabrück and Münster, largely ending the European wars of religion. The treaties of Westphalia brought to a close a calamitous period of European history which caused the deaths of approximately eight million people. Scholars have identified Westphalia as the beginning of the modern international system, based on the concept of Westphalian sovereignty. The negotiation process was lengthy and complex. Talks took place in two different cities, as each side wanted to meet on territory under