The narrative cycles rest on a painted dado. This complements the pictorial program, and proves to be one of the inventions with which Giotto renewed art, even in what is supposed to be only a secondary setting.
Two very realistically painted, multi-colored panels of marble alternate respectively with depictions of figures. The personifications of the Vices on the one side, and of the Virtues on the other, appear here as marble sculptures brought to life. However, they are not made of stone. This kind of tone-on-tone painting (grisaille) is just as novel as the view into a painted sacristy, which Giotto displays above the marble dado on either side of the triumphal arch. Here, painted and real space once again merge into one. Using a very clear perspective — with a common vanishing point — Giotto depicts two views of an interior space with cross-rib vaulting, whose dimensions are suggested by the lamp which hangs from the ceiling.