Can you imagine a Danish Protestant (1638-1686) and natural scientist becoming a German catholic bishop? It happened! Niels Stensen, in the then usual latinized form Nicolaus Steno was at his time a leading natural scientist, famous as physician, anatomist, crystallograph, mineralogist and geologist. He was the son of a goldsmith. His mother was the daughter of a famous family of protestant pastors. He started his studies in Copenhagen in medicine, mathematics and philosophy and became a polymath well known across Europe.

As anatomist he became well known across Europe by his public demonstrations of anatomical dissections in the so called Theatrum Anatomicum, a kind of public science in these days. You had to pay - like in a modern cinema - a fee to get access to these anatomical lectures in which you were entertained by a medical doctor about the wonders of the human body. Stensen was a great scientific entertainer. As anatomist he discovered the glands for tears and saliva, as mineralogist he discovered the constancy of the angle of crystals irrespective of form and size, as geologist he was the first to find out in his dissertation De solido that the various layers of geological sediments correspond with their age. He thus became the founding father of modern geology and crystallography.

What makes him interesting however as predecessor of modern evolutionary theory is not only the fact that he introduced in geology the above mentioned historical perspective but also his interpretation of fossils. In his time fossils were seen as natural forms of stones. He in contrast to this view interpreted rightly fossils as petrifactions of former organisms or parts of organisms. For example so called tongue stones (Stenoshark) he interpreted as petrifactions of shark teeth.

His scientific endeavors however were part of his religious belief. In the theological tradition of seeing in nature the traces of God he for instance saw in anatomy - like his later colleague Lorenz Heister - a means of recognizing and praising God. Thus he wrote: "This is the true purpose of anatomy: To lead the audience by the wonderful artwork of the human body to the dignity of the soul and by the admirable structure of both to the knowledge and love of God." (Opus philosophicum II, 254).

Stensen lead a very adventurous life, travelling across Europe. He stayed in Germany, The Netherlands, France, Italy and Eastern Europe. Wherever he was he had contact with the contemporary leading scientists and learned societies, then often informal conventions. He was acquainted with Spinoza, Leibniz and many other luminaries of his time. When he was in The Netherlands and in Italy he became more and more interested into religion, in The Netherlands because of the many Calvinist sects in Italy because of the impressing conformity of Catholicism and the personal convincing life the outstanding catholic personalities, like the reform bishop Borromaeus. Due to this kind of impressing personal holiness he eventually converted to Catholicism and became an ordained priest. After serving as a lecturer in anatomy at his own university in Copenhagen, already catholic, he went back to Italy and became after a couple of other locations where he served the Church, like Munster and Hamburg, the bishop of the little catholic congregation in Schwerin. He died in the age of 48 and became beatified in 1988 by Pope John Paul II.

The next person introduced as forerunner of Charles Darwin will be William Paley.

Wolfgang Achtner