Much has been written about the identity of the sitter in this portrait. In 1568, Vasari noted that Pontormo painted a beautiful work, a portrait of Francesco Guardi. In 1612, however, the name of Cosimo i de' Medici was attached to a description of the portrait. In this volume, Cropper argues that the subject of the painting is indeed Francesco Guardi. She discusses not only the specific determination of the sitter but the tools and methods used in general for establishing the people and places portrayed in works of art.