All the marble panelling, pilasters, niches, and so forth, which at present clothe the walls and dominate the architectural effect, are clearly planned for mural monuments.

A rude sketch preserved in the Uffizi throws some light upon the intermediate stages of the scheme.

It is incomplete, and was not finally adopted; but we see in it one of the four sides of the chapel, divided vertically above into three compartments, the middle being occupied by a Madonna, the two at the sides filled in with bas-reliefs.

At the base, on sarcophagi or _cassoni_, recline two nude male figures.

The space between these and the upper compartments seems to have been reserved for allegorical figures, since a colossal naked boy, ludicrously out of scale with the architecture and the recumbent figures, has been hastily sketched in.