Sixteenth-century Venice was a creative lab in which physiognomy was undergoing major transformation. The development of art theory, especially the theory of proportions, as well as a new attention to direct observation, parallel to developments in anatomy, decisively enriched physiognomic knowledge and practice, thus defining more refined criteria for reading the external, bodily “signs of nature in man”—as reads the title of Antonio Pellegrini's 1545 physiognomic dialogue. In this framework, the particularities of criminal physiognomies entered into physiognomists’ scope of interest, and the direct observation, description, and explanation of bodily signs that could reveal an inclination to crime naturally took on a decided importance in physiognomic treatises. This interest in criminals went hand in hand with the special attention that jurists and judges gave to physiognomy. As an aspect of judicial procedure, physiognomy supplied a critical tool that allowed jurists and judges in court to ground their judgment of a defendant's body when assessing the likelihood of whether the accused committed a crime.