Pustulotic arthro-osteitis probably associated with retroperitoneal fibrosis has been diagnosed in Erasmus of Rotterdam, based on paintings of Quentin Massys (1517) and Hans Holbein the younger (1523), historical letters of Erasmus, and postmortem examination of the skeleton. This case report is a description of the earliest known case of pustulotic arthroosteitis, a syndrome reported for the first time in 1%7 and seen more commonly in Japan than in Europe. Works of art of many different kinds may provide an important source of evidence of disease and contribute to a better understanding of the natural history of a disease.