Nicolas Steno (;
Latinized to
Nicolaus Stenonis or
Nicolaus Stenonius; 1 January 1638 – 25 November 1686 ) was a
Danish scientist, a pioneer in both
anatomy and geology who became a Catholic
bishop in his later years. Steno was trained in the classical texts on science; however, by 1659 he seriously questioned accepted knowledge of the natural world. Importantly he questioned explanations for tear production, the idea that fossils grew in the ground and explanations of rock formation. His investigations and his subsequent conclusions on fossils and rock formation have led scholars to consider him one of the founders of modern
stratigraphy and modern geology.