The Ducal Castle is a complex of building built in 1356 that served not only as the residence of the Duke: it housed the city administration, the strategic reserves of provisions were stored in it and the walls and towers of the castle strengthened the city's fortifications. Later, the Treasury, garrison and social apartments were here. Today, the city archive, the financial department and the library occupy part of the building.
The Knights' Hall is open for visits. In the old days it was used for feasts and court hearings. Today, it hosts concerts. The residence was built in the late-Gothic ascetic style, but one building stands out with its view. The residence of the ducal governor was rebuilt in the style of French Rococo and the background of the severe walls of the castle looks pretty pretentious.