A completely new interior, in the western segment added in 1788, was the two-tiered Ballroom with decorations designed by Jan Chrystian Kamsetzer. Completed in 1793, it constituted an outstanding example of the classicist style in Poland. The stuccowork and mural decorations were subordinated to architectural divisions. The axis of the composition was set off by two monumental marble fireplaces in the form of wall porticoes, featuring statues of Apollo and Farnesian Heracles set against the shorter walls. The longer, white marbled walls decorated by vertical panneaux, painted by Jan Bogumił Plersh in the style of Raphael's grotesques in the Vatican. Gold was the dominant colour in all chambers, especially in Solomon's Hall. The plafond, bed-mouldings and both longer walls were filled with paintings by Marcello Bacciarelli illustrating the life of King Solomon. It was also during the time that the interior of the former baroque grotto at the centre of the building was changed into something exceptionally monumental and serious. The walls were stuccoed in gold, grey and white and were divided with half-columns (between which neighbouring premises were entered) as well as four niches containing the marble statues of the greatest Polish monarchs: Casimir III the Great, Stefan Batory, Sigismund III and John III Sobieski. The cupola contained four tondi painted by Bacciarelli symbolizing the four virtues exemplified by the monarchs: courage, wisdom, justice and mercy. They concealed (in 1795) earlier frescos by Plersch illustrating the times of the day which had been in keeping with the interior's previous climate.