No old man ever forgot where he buried his treasure: concepts of cognitive impairment in old age circa 1700.

Cognitive impairment in old age is one of the most important topics in modern geriatrics. This article discusses the historical dimensions of this phenomenon. To this end, a number of primary sources ranging from antiquity to the modern era are evaluated. Although a physiology and pathology of old age were conceptualized in Greco-Roman times, cognitive impairment in old age remained a marginal issue until the 17th century. Alternatively, after 1500, medicine boasted detailed theories on the physiology and pathology of old age. There are several possible explanations for this unusual situation. Underlying conflict between idealistic and materialistic views of man played a decisive role, for these concepts differed considerably regarding the intellectual and mental functioning of the soul as well as the effects of the passage of time. After Cartesianism and Iatromechanism had pushed these traditional boundaries back, the problem of cognitive impairment in old age was increasingly regarded as a physical illness and began to receive more attention. Just as its philosophical and theological context shaped early modern medicine, contemporary nonmedical disciplines such as genetics, (neuro-)biology, and the information sciences influence modern research.