Existing accounts of the early history of Alzheimer’s disease have focused on Alois Alzheimer’s (1864–1915) publications of two ‘peculiar cases’ of middle-aged patients who showed symptoms associated with senile dementia, and Emil Kraepelin’s (1856–1926) discussion of these and a few other cases under the newly introduced name of ‘Alzheimer’s disease’ in his Textbook of Psychiatry. This article questions the underpinnings of these accounts that rely mainly on publications and describe ‘presenility’ as a defining characteristic of the disease. Drawing on archival (...) research in the Munich psychiatric clinic, in which Alzheimer and Kraepelin practised, this article looks at the use of the category as a diagnostic label in practice. It argues that the first cases only got their exemplary status as key referents of Alzheimer’s disease in later readings of the original publications. In the 1900s, the published cases rather functioned as material to think about the limits of the category of senile dementia. The examination of paper technologies in the Munich psychiatric clinic reveals that the use of the clinical diagnosis of Alzheimer’s disease was not limited to patients of a certain age and did not exclude ‘senile’ cases. Moreover, the archival records reflect that many diagnoses of Alzheimer’s disease were noted in the medical records as suspicions rather than conclusions. Against this background, the article argues that in theory and practice, Alzheimer’s disease was not treated as a well-defined disease entity in the Munich clinic, but as an exploratory category for the clinical and histopathological investigation of varieties of organic brain diseases. (shrink)