When the duke died in 1800, his eldest daughter Katharina Wilhelmine (1781–1839) inherited Náchod and the Duchy of Sagan. She also kept a palace in Vienna and had close contacts with many political figures of the time (chancellor Metternich, general Prince Windischgrätz, British ambassador Lord Charles Stewart, tsar Alexander I, etc.). Her palace was one of the favourite venues of the Congress of Vienna. After the death of the Duchess of Sagan, the princes of Schaumburg-Lippe (in today’s Lower Saxony) bought Náchod and held the castle till 1945, though the herrschaft system was abolished in the reform of 1849 and succeeded by public administration districts.