A copy of Athansasius Kircher’s Mundus subterraneus is without doubt one of the most beautiful books in the Fagel Collection. The colouring is of an exceptional quality, initials and captions are heightened with gold throughout the book. Samuel Paterson, who compiled the Fagel auction catalogue for Christie’s in 1802, described it ‘a matchless copy, illuminated in the style of the ancient missals’. Time to take a closer look at this copy. Why did the otherwise so modest Fagels own such a lavishly decorated book?