The first Leiden alumnus to make an international name for himself in geology was the brilliant Dane Niels Stensen. He is also known by physicians and geologists as Nicolaus Stenonius or Steno (in Italy as Niccolò Stenone, in France as Sténon).
Stensen studied in Leiden from 1660. In 1664, he received his doctorate in absentia cum laude, unique in the history of Leiden University. During his travels through the Low Countries and Europe, he developed his geological ideas, which form the basis of much of what we know about earth science today.
Stensens famously said: Pulchra sunt qvae videntur, pulchriora qvae sciuntur, longe pulcherrima qvae ignorantur. (Beautiful is what we see. More beautiful is what we understand. Most beautiful is what we do not comprehend.)