The last Archbishop and Elector of Trier, Clemens Wenceslaus, commissioned this riverside palace in 1777 as a more comfortable residence than Ehrenbreitstein across the water. He had barely moved in when Napoleon's troops arrived in 1794 and turned it into a barracks; it has been an administrative building, a Prussian royal residence, and a Wehrmacht headquarters since.
It is one of the last great classical palaces of the Holy Roman Empire and one of the few major Koblenz buildings that the Allies were careful not to bomb in 1944. The state rooms on the first floor are occasionally open to the public; the gardens running down to the Rhine are free at any hour.