The square vault, illusionistically subdivided into an umbrella, houses the monochrome (grisaille) portraits of the nine muses and Apollo, derived from the so-called Mantegna tarot, in the sails and lunettes, while the oculus at the center opens on the sky, which three figures (an old man, a woman and a boy) are protruding, is a quotation from the Camera degli Sposi in Mantua. In the lunettes, arranged in pairs, the profiles of the Roman emperors and their respective wives are represented, except for two in which are depicted Apollo and the muse Calliope. The frescoes were torn in 1887 by Giuseppe Steffanoni on behalf of the Florentine antiquarian Stefano Bardini and sold two years later to the Victoria & Albert Museum in London.