Nicolas Steno (Danish: Niels Stensen; latinized to Nicolaus Stenonis, Italian Niccolo' Stenone) (11 January 1638 - 25 November 1686) was a Danish pioneer in both anatomy and geology. Already in 1659 he decided not to accept anything simply written in a book, instead resolving to do research himself. He is considered the father of geology and stratigraphy.