Today, the palace houses the art gallery Gemäldegalerie Alte Meister, part of Museumslandschaft Hessen Kassel.

The current Neoclassical Schloss Wilhelmshöhe was designed by architects Simon Louis du Ry and Heinrich Christoph Jussow [de] from 1786 to 1798 for Landgrave William IX of Hesse.

[1] 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.

In 1918, after the armistice ended World War I, the Oberste Heeresleitung, the High Command of the Germany Army under Paul von Hindenburg was moved here from Spa (Belgium) to organize and lead the withdrawal and demobilization of the German troops.

William I, Elector of Hesse, as well as Jérôme Bonaparte, assembled a large collection of Empire style furniture.