Renaissance artists revived the mosaic technique from the early Christian period, considering it particularly appropriate for commemorative portraits since mosaic tiles, composed of ceramic or glass, preserved their color more permanently than paintings. Giovanni Battista Calandra here depicts Camillo Rospigliosi, brother of Pope Clement IX and Knight Commander of the Order of Santo Stefano, whose cross insignia adorns his chest.
Despite the medium's technical challenges, Calandra reproduces some of the naturalistic techniques of contemporary painting. He may even have copied a painting, as was common practice among mosaicists. Calandra positions the sitter at a slight angle, employing perspective to represent the foreshortened chest and shoulders. In addition, he carefully renders the gradations of hair color resulting from changes in light and sfumato, the effect of light giving way to darkness behind the sitter. The embroidered cross showing through Rospigliosi's collar is a notable tour de force in subtle coloring. The portrait may have been part of a funerary monument or, alternately, Rospigliosi may have displayed it in his home.