Bernard Berenson,
The Venetian Painters of the Renaissance
“ Donatello's bust of Niccolò d'Uzzano shows clearly, nevertheless, that the Renaissance could not long remain satisfied with the sculptured portrait. It is coloured like nature, and succeeds so well in producing for an instant the effect of actual life as to seem uncanny the next moment. Donatello's contemporaries must have had the same impression, for busts of this kind are but few. Yet these few prove that the element of colour had to be included before the satisfactory portrait was found: in other words, that painting and not sculpture was to be the portrait-art of the Renaissance. ”

