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).
John Sigismund, Elector of Brandenburg John Sigismund, Elector of Brandenburg John Sigismund (; 8 November 1572 – 23 December 1619) was a Prince-elector of the Margraviate of Brandenburg from the House of Hohenzollern. He became the Duke of Prussia through his marriage to Duchess Anna, the eldest daughter of Duke Albert Frederick of Prussia who died without sons. Their marriage resulted in the creation of Brandenburg-Prussia. John Sigismund was born in Halle an der Saale to Joachim III Frederick, Elector of Brandenburg, and his first wife Catherine of Brandenburg-Küstrin. He succeeded his father as Margrave of Brandenburg in 1608. In 1611, John Sigismund traveled from