Brandenburg-Schwedt his dominions and furnishing his castle in a Baroque style at great expense. His younger brother Albert Frederick (1672–1731) became a general lieutenant and Grand Master of the Order of Saint John; the third-born, Charles Philip (1673–1695) likewise became an officer and shortly before his death secretly married the Piemontese noblewoman Caterina di Balbiano, who called herself "Madame de Brandebourg" as a widow. The youngest of Dorothea's sons was Margrave Christian Ludwig (1677–1734), officer and administrator of Halberstadt, the honoree of Bach's "Brandenburg Concertos". The brisk building activity was continued by Philipp William's son and successor, Margrave Frederick William (1700-1771).
Brandenburg-Prussia the Catholic-Imperial camp in the Treaty of Königsberg (1627) and accept garrisons. When the Swedish Empire entered the war and advanced into Brandenburg, George William again claimed neutrality, yet Gustavus Adolphus of Sweden compelled George William to join Sweden as an ally by occupying substantial territory in Brandenburg-Prussia and concentrating an army before the town walls of Berlin. George William did not conclude an alliance, but granted Sweden transit rights, two fortresses and subsidies. Consequently, Roman Catholic armies repeatedly ravaged Brandenburg and other Hohenzollern lands. During the Thirty Years' War, George William was succeeded by Frederick William, born 1620, who