The major morphological types of conjoined twins had all been described by 1600, often in publications that included details of the time and place of birth, morphology, outcome, behaviour, and, on occasion, autopsy findings. These descriptions differ from modern reports in emphasizing the twins’ supposed “meaning” rather than their cause. Understanding the symbolic aspects of these accounts is important for their interpretation. This article summarizes the records of 53 cases of conjoined twins born in 16th-century Europe and examines the cultural background of these accounts and the use of the pediatric autopsy as a means of investigating the pathology of twins. Studies of conjoined twins were central to the debate over whether the possession of separate hearts was a prerequisite for individuality.