The Old Orangery

The theatre in the east wing of the Old Orangery is one of the most remarkable features of the building. The theatre is elaborately decorated and remains one of the few authentic 18th-century court theatres in the world. The audience area accommodated about 200 people and included a ground floor with benches arranged in an amphitheatre fashion and three boxes on each wall. The walls between the boxes were adorned with pilaster statues of women holding candles, which were the work of Andrzej Le Brun. Illusionary boxes were painted above the real boxes, and the stage featured painted bas-reliefs of coats-of-arms with the crest of the Polish-Lithuanian Commonwealth at the center. The theatre's interior was constructed entirely of wood to ensure excellent acoustics. The deep stage has a slanted floor and features fragments of the equipment of a former engine-room.

The west wing of the Old Orangery is home to the Gallery of Polish Sculpture. The gallery exhibits works dating from the 16th century up to 1939. Room 1 showcases sculptures dating from the 16th and 17th centuries, as well as the first half of the 18th century, while the next room features works from the latter half of the 18th century, including works by Jan Jerzy Plersch, Franciszek Pinck, and Andrzej Le Brun. The mid-19th century sculptures by artists such as Paweł Maliński, Jakub Tatarkiewicz, Władysław Oleszczyński, Marceli Guyski, and Henryk Sattler can also be seen.