Cabinets of curiosities (also known as Wunderkammer or wonder-rooms) were collections of natural history artifacts kept by many early practitioners of science in Europe, and were precursors to natural history museums.
Two of the most famously described cabinets were those of Ole Worm (also known as Olaus Wormius) and Athanasius Kircher. These 17th-century cabinets, actually room-sized collections, were filled with preserved animals, horns, tusks, skeletons, minerals, and so on. Often they would contain a mix of fact and fiction, including apparently mythical creatures. Worm's collection contained, for example, what he thought was a Scythian Lamb, a wooly fern thought to be a plant/sheep fabulous creature. The specimens displayed were often collected during exploring expeditions and trading voyages.
Cabinets of curiosities would often serve scientific advancement when images of their contents were published. The catalog of Worm's collection, published as the Museum Wormianum (1655), used the collection artifacts as a starting point for Worm's speculations on philosophy, science, natural history, and more.
Obviously cabinets of curiosities were limited to those who could afford to create and maintain them. Many monarchs, in particular, developed large collections. Frederick III of Denmark, who added Worm's collection to his own after Worm's death, was one such monarch. Another example is the Kunstkamera founded by Peter the Great in Saint Petersburg in 1727.