Post-traumatic stress disorder was first recognized as a diagnostic category embracing reactions in response to overwhelming environmental stress 'outside the range of usual human experience' in DSM-III (APA, 1980). Such abnormal stressors are by no means a product of the twentieth century but have featured, sporadically, in all societies from the earliest civilizations. Longitudinal investigations of traumatic stress have rarely gone further back than the nineteenth century, and have been concerned, almost exclusively, with adverse effects following railway accidents and military combat. The present study, utilizing a mid-eighteenth century medical source, presents an analysis of the impact of a natural disaster on members of a peasant family trapped in an avalanche in the Italian Alps in 1755.