As king of the Kingdom of Westphalia, Jérôme Bonaparte renamed it "Napoleonshöhe" and appointed his Head Chamberlain Heinrich von Blumenthal as its governor, with instructions to supervise extensive renovations and alterations such as the side wings between the three buildings. After his kingdom ceased to exist when France lost the Battle of the Nations on 19 October 1813, the Elector of Hesse-Kassel returned. When his state was annexed by Prussia in 1866 following the Austro-Prussian War, the palace passed from the House of Hesse to the House of Hohenzollern. After the Franco-Prussian War of 1870/71, the Prussian King offered the defeated Emperor Napoleon III accommodation there, but after half a year the Emperor went into exile in England.