The lump on the left breast of the Night (Figure 1.1), a marble sculpture carved by Michelangelo in the 1520s, forces us to reconsider a series of widely held views, from the artist’s reputed ignorance of female anatomy to the modern fascination 4with medical diagnoses of art. 1 Before turning to the sculpture, the first section considers some methodological problems posed by retrospective diagnoses through art. As discussed in the second section, the breast of the Night shows the physical signs of advanced cancer, and it is portrayed in such a way to suggest that Michelangelo made a conscious decision to represent an infirmity. This all-too-human element alludes to death, an appropriate subject for the decoration of the Medici mausoleum in the Church of San Lorenzo, Florence, known since the sixteenth century as the New Sacristy. Moreover, early sources often refer to cancer as gnawing into flesh, and this metaphor complements perfectly Michelangelo’s overall conceit for the tomb: ‘time devours all things’. The third section presents the hypothesis that Michelangelo associated Night with the melancholic temperament, given that doctors then believed that the disease of melancholia could lead to cancer. The poses and body types of the four allegorical statues in the New Sacristy—Night and Day on the tomb of Duke Giuliano (Figure 1.2), and Dawn and Dusk on the tomb of Duke Lorenzo (Figure 1.3)—seem to reflect the four canonical temperaments.