Between the lunettes and the spandrels depicting Christ's ancestors are the Prophets and Sibyls, who appear to be much larger than they really are. The violence and the power of these figures, however, is not due to their superhuman size, but mostly to their isolation. Each of these figures, in its own way, seems totally enraptured in the spiritual act of contemplation, intuition and ecstasy; they seem the personification of that divine spirit which briefly at times uses them as agents in communicating to other men.

It is not known who or what determined Michelangelo to evoke the seven Prophets, and from some primeval limbo the five Sibyls. It may well be that theologians gave the young artist some direction, but it was he who breathed new life into their abstract ideas. This inspiration animates the entire composition within its trompe-l'oeil frame.

Brilliant composition and the use of additional figures makes the Prophets' zone of individual souls extend into the lower, material, and the upper, spiritual, zone. The majestic and at the same time naturalistic seated figures minimize the twelve spandrels and absorb them into their own sphere. Twelve different types of awakened man conform there to a single pattern, expanded by the subsidiary figures beside and above their thrones into twelve splendid variations. The throne of each Prophet and Sibyl is raised on a console inscribed with his or her name. Each console is supported by a boyish elemental telamone; each figure is flanked by square pedestals forming a niche for the Prophet or Sibyl surmounted by twin putti in relief. As a background to each enthroned figure, two small angels are in evidence in varying degrees.