This marble sculpture has been identified with the statue depicting the prophet Isaiah which, as we learn from documentary sources, was created in 1408 by the early Renaissance sculptor Nanni di Banco, friend and collaborator of Donatello, for one of the external buttresses of the Cathedral and then placed in the unfinished medieval facade. When the facade was dismantled in 1587, the statue was placed in the current aedicule in marbled wood, designed by Bartolomeo Ammannati. The young prophet is depicted with that noble pride inspired by the ancient Roman statuary that distinguishes the first works of the Florentine fifteenth century, an artistic expressions of the concept of human dignity rediscovered by the Renaissance culture. Isaiah is in a resting pose, swaying on his right leg. He holds the cartouche with his own prophecies in the left hand, while with his right he holds up a flap of the cloak that wraps it. The head, of a beardless and curly young man, turns to look at the horizon of future events with a confident look and a hint of a smile.