The interior was part of the 17th century pavilion of the Lubomirski’s Bathhouse. In 1772, it was given a new architectural arrangement which conformed to the preferences of the new owner, as well as a new function – of the Royal bedchamber. It was decorated with colourful yellow and red stuccos, and the ceiling was covered with a whimsical painting emulating the sky, and framed with a laurel wreath. Many portraits hung here including the portraits of Stanisław August’s parents. In 1784, the southern side of the room was expanded and gained a new function: it became a dining room into which – for the dinner time – tables were brought from the kitchen building. The decor of the rectangular Dining Room is relatively modest, but it is characterised by refined and cool elegance. It owes its beauty to the marbleised walls with contrasting, straight, geometric divisions made of panels in the colour of porphyry. A pair of stucco columns in the same colour adds gravity to the interior. Porphyry-based decorations are typical of the art of the late Antiquity; it is a possible reason why this colour was selected for the decorations of the new Stanislavian interiors – designed in the spirit of Classicism. Today, the rather raw decor is complemented with busts of the following Roman emperors standing on pedestals: Caracalla, Julius Ceasar, Galba, and Hadrian. They are copies of Ancient sculptures – made on the request of Stanisław August. This type of sculpted decoration also adorned the Versailles’ apartments in the time of Louis XIV. It is worth paying attention to the Antique-styled bust of Stanisław August, portrayed as an Ancient ruler – with hair tied with a band, and wearing armour. It was made by Domenico Cardelli from Italy. What is interesting, although the artist had never travelled to Poland – he was given the title of the “Sculptor of his Royal Majesty Stanisław August”. Another important work of art is the Bust of Diana; it is a copy of the original sculpture by Jean Antoine Houdon from the old Royal collections.

The function of the Dining Room was highly elevated. It was here that the Thursday Dinners took place in the summer season. They were an unprecedented phenomenon in the Enlightened Europe of the period. They followed the convention of French meetings, in which Stanisław August used to take part during his stay in Paris – in the salon of Mrs. Geoffrin – a place of scholarly discussions of the luminaries of science and culture of the period. The special nature of the Polish “intelligent dinners” – as they were called at the time – was due to the fact that the King himself participated in them, and the fact that they fulfilled unofficially the function of a state institution. This was the place for discussing matters which would later be presented before the Sejm, and often become official laws. Considering the above, it is possible that the busts of Roman emperors were placed in the location where important state issues were discussed in order to allude to the topos of conversations between the living and the dead on the Elysian Fields, which was popular in the Enlightenment and derived from the Aeneid by Virgil – widely read in the period.