After completing his statue of St Mark, Donatello hastened to complete the St John which was to be placed on the façade of Santa Maria del Fiore in the tabernacle at the side of the central door. This statue, which was commissioned by the Opera del Duomo, almost seems to anticipate the works of Michelangelo. Particularly remarkable are the saint’s acute and penetrating expression, and the realistic treatment of his open hand on the book.
This statue represents one of the clearest examples of how perspective is achieved. To offset the apparent distortion that would result from the statue being seen from below, the Evangelist’s body has been made disproportionately long for his legs and thighs, which project little from the surface of the statue.
In 1587 the St John, along with the other Evangelists, was removed from the façade and placed inside the Cathedral, whence it was finally moved to its present place in the Museum of the Opera del Duomo.
Reed Enger, "St. John the Evangelist," in Obelisk Art History, Published January 23, 2015; last modified June 02, 2020, http://arthistoryproject.com/artists/donatello/st-john-the-evangelist/.