Da Vinci, who lived between 1452 and 1519, is widely regarded as the exemplar “Renaissance man,” in humanist terms. This Italian polymath made revolutionary contributions in the areas of painting, music, science, architecture, mathematics, engineering, botany, writing, history, astronomy, and cartography. He is sometimes credited with inventing the helicopter, parachute, and tank, more than 300 years before these technologies reached mass-production levels. With his vast curiosity, da Vinci is commonly believed to have been the most talented individual ever to have lived, and thus his character is a fruitful one for Freud’s analysis.

Grimm’s Dictionary, or the Deutsches Worterbuch (DWB) is the largest compendium of the German language in existence. It encompasses modern High German since 1450, and it is one of the sources that Freud cites in when he is establishing the definition of the unheimlich that will support his arguments in the later phases of the essay. 

Freud makes reference to the following quote from playwright Karl Gutzkow during the discussion of the semantics of heimlich. The phrase comes from the novel Die Ritter vom Geist (1851), and is proceeded by a brief example of the heimlich, which Freud does not quote but alludes to.