The notion of what qualifies as vascular dementia has varied greatly since the first mention of dementia after apoplexy in ancient literature. Current insight points towards a multifactorial cause of cognitive decline at old age, in which vascular components like atherosclerosis, arterio(lo)sclerosis, (micro)infarcts, and amyloid angiopathy play an important role alongside other markers of neurodegeneration. Cerebrovascular disease will be present in most individuals with dementia, but—just like other causes—rarely a cause on its own. The consequent limitations of nosology may be alleviated by addition of a vascular component to the recently introduced amyloid/tau/neurodegeneration etiological classification system for dementia. Meanwhile, risk of dementia is increased about 2-fold after stroke, and the prevention of (recurrent) stroke remains a cornerstone in the prevention of vascular dementia. Similarly, control of cardiovascular risk factors from middle age onwards is likely to have contributed to the reported decline in the age-specific incidence of dementia over the past decades. In conjunction with experimental studies, large-scale observational evidence from imaging, genomics, metabolomics, and alike will continue to improve our understanding of the underlying pathophysiological processes. To prevent ecological fallacies, such etiological studies in patients with dementia are best served by inclusion of subjects regardless of the presumed (single) cause of their disease.