Editing Nicolas Steno (section)

== Early life and career ==
[[File:Portrait of Nicolas Stenonus.jpg|thumb|left|upright|Portrait of Niels Steensen (1666–1677). Unsigned but attributed to court painter [[Justus Sustermans]]. ([[Uffizi Gallery]], Florence, Italy).{{sfnp|Hansen|2009|p=161}}]]
Niels Steensen was born in [[Copenhagen]] on New Year's Day 1638 ([[Julian calendar]]), the son of a [[Lutheran]] [[goldsmith]] who worked regularly for King [[Christian IV of Denmark]]. He became ill at age three, suffering from an unknown disease, and grew up in isolation during his childhood. In 1644 his father died, after which his mother married another goldsmith. In 1654–1655, 240 pupils of his school died due to the [[Black Death|plague]]. Across the street lived [[Peder Griffenfeld|Peder Schumacher]] (who would offer Steensen a post as professor in Copenhagen in 1671). At the age of 19, Steensen entered the [[University of Copenhagen]] to pursue medical studies.{{sfnp|Kermit|2002}} After completing his university education, Steensen set out to travel through Europe; in fact, he would be on the move for the rest of his life. In the Netherlands, France, Italy and Germany he came into contact with prominent physicians and scientists. These influences led him to use his own powers of observation to make important scientific discoveries.

At the urging of [[Thomas Bartholin]], Steensen first travelled to [[Rostock]], then to [[Amsterdam]], where he studied anatomy under and lodged with [[Gerard Blasius]], focusing on the [[lymphatic system]]. Within a few months Steensen moved to Leiden, where he met the students [[Jan Swammerdam]], [[Frederik Ruysch]], [[Reinier de Graaf]], [[Franciscus Sylvius|Franciscus de le Boe Sylvius]], a famous professor, and [[Baruch Spinoza]].{{sfnp|Kooijmans|2004|p=53}}{{sfnp|Kooijmans|2004}} Steensen doubted [[René Descartes|Descartes's]] recently published explanation of the origin of tears<ref>{{cite web|last= René|first= Descartes|title= The Origin of Tears|url= http://www.earlymoderntexts.com/pdf/descpass.pdf|work= The Passions of the Soul|publisher= Jonathan Bennett|access-date= 11 January 2012}}</ref> as produced by the brain. Invited to Paris by [[Henri Louis Habert de Montmor]] and [[Pierre Bourdelot]], he there met [[Ole Borch]] and [[Melchisédech Thévenot]] who were interested in new research and in demonstrations of his skills. In 1665 Steensen travelled to [[Saumur]], Bordeaux and [[Montpellier]], where he met [[Martin Lister]] and [[William Croone]], who introduced Steensen's work to the [[Royal Society]].

After travelling through France, he settled in Italy in 1666 – at first as professor of anatomy at the [[University of Padua]] and then in Florence as in-house physician of [[Ferdinando II de' Medici, Grand Duke of Tuscany|Grand Duke of Tuscany Ferdinando II de' Medici]], who supported arts and science and whom Steensen had met in [[Pisa]].{{sfnp|Chisholm|1911}} Steensen was invited to live in the [[Palazzo Vecchio]]; in return he had to gather a [[cabinet of curiosities]]. Steensen went to Rome and met [[Pope Alexander VII]] and [[Marcello Malpighi]], whom he admired. On his way back he watched a [[Corpus Christi (feast)|Corpus Christi]] procession in [[Livorno]] and wondered if he had the right belief.<ref>Kooijmans, L. (2007) Gevaarlijke kennis, p. 99-100.</ref>