In 2006, we celebrated the 350th anniversary of the beginning of an extraordinary career. On 27 November 1656, Niels Stensen, also known as Steno, commenced his studies at the University of Copenhagen, Denmark. All through his scientific life, Steno was fortunate to be able to name many famous scholars amongst his acquaintances, including experts in, for example, chemistry, mathematics, pharmacy, medicine, and biology. He was also supported financially by patrons with a keen interest in natural history. Many of these people were also associated with collections or museums of reputation. Some had inherited collections or museums, e.g., Jan Swammerdam and Manfredo Settala, and others had established these themselves, e.g., Athanasius Kircher. Steno eventually became a collector and curator for the Grand Duke of Tuscany. This work is documented in a catalogue, Indice di Cose Naturali, listing amongst other naturalia samples of minerals and fossils in the Grand Duke’s collection, some collected by Steno himself. Examples are hematite crystals from Elba, collected before De Solido reveals the principles of “Steno’s law” in 1669, and fossil fish from the copper shale in Eisleben, collected later. The importance of the Indice (the Index) is that the samples listed were partly collected by Steno as documentation for his own research and inspection of economically important geological localities. In posterity, the late Dr. Gustav Scherz was able to reconstruct Steno’s travels using the information of these samples.

There is only scattered information on Steno’s interest and experience with collections or museums in his publications and letters. The aim of this paper is to throw light upon this relatively unknown part of his life from the very beginning of his career. This study demonstrates that Steno encountered many of the most important collections and museums in Europe during the period of his life, which was dedicated to science. Steno was a marvelous analytical observer with a unique scientific approach. It therefore seems obvious that this encyclopedic multitude of impressions and information from the caretakers and other sources must have been of significance, not only for his own museological work, but also for his outstanding ability to contribute to new discoveries in anatomy as well as in geology.