Editing Nicolas Steno (section)

== Conversion and priesthood ==
Steensen's questioning mind also influenced his religious views. Having been brought up in the [[Lutheran]] faith, he nevertheless questioned its teachings, something which became a burning issue when confronted with [[Catholic Church|Catholicism]] while studying in [[Florence]]. After making comparative theological studies, including reading the Church Fathers and by using his natural observational skills, he decided that Catholicism, rather than Lutheranism, provided more sustenance for his constant inquisitiveness. In 1667, Steensen converted to Catholicism on [[All Souls' Day]], influenced, among others, by Lavinia Cenami Arnolfini, a noblewoman of [[Lucca]].{{sfnp|Cheney|2022}}<ref>{{cite web |title=Niels Stensen |url=http://www.whonamedit.com/doctor.cfm/2052.html |work=Whonamedit? A dictionary of medical eponyms |access-date=11 January 2011}}</ref>

Steensen traveled to Hungary, Austria and in Spring 1670 he arrived in Amsterdam. There he met with old friends [[Jan Swammerdam]] and [[Reinier de Graaf]]. With [[Anna Maria van Schurman]] and [[Antoinette Bourignon]] he discussed scientific and religious topics. The following quote is from a 1673 speech:
:''Fair is what we see, Fairer what we have perceived, Fairest what is still in veil''.<ref>{{cite web |url=http://www.stenomuseet.dk/engelsk/mellem.htm |title=Pulchra sunt, quae videntur pulchriora quae sciuntur longe pulcherrima quae ignorantur. From a 1673 speech for the Copenhagen Anatomical Theatre |publisher=Stenomuseet.dk |access-date=11 January 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120320180636/http://www.stenomuseet.dk/engelsk/mellem.htm |archive-date=20 March 2012  }}</ref>
It is not clear if he met [[Nicolaes Witsen]], but he did read Witsen's book on shipbuilding. In 1671 he accepted the post of professor of anatomy in the University of Copenhagen,{{sfnp|Chisholm|1911}} but promised [[Cosimo III de' Medici]] he would return when he was appointed tutor to [[Ferdinando III de' Medici]].

At the beginning of 1675, Steensen decided to continue his theological studies, which he had begun even before his conversion, toward his ordination to the priesthood.{{sfnp|Kraus|2011|p=35}} After only 4 months, he was ordained priest and celebrated his first Mass on 13 April 1675 in the [[Santissima Annunziata, Florence|Basilica of the Santissima Annunziata]] in Florence at the age of 37.{{sfnp|Scherz|2002}}{{sfnp|Cheney|2022}}{{sfnp|Kraus|2011|p=35}} [[Athanasius Kircher]] expressly asked what were the reasons why he decided to become priest.{{sfnp|Kraus|2011|p=35}} Steensen had left natural sciences for education and theology and became one of the leading figures in the [[Counter-Reformation]].{{sfnp|Garrett Winter|1916|p=182}} Upon request of Duke [[John Frederick, Duke of Brunswick-Lüneburg|Johann Friedrich of Hanover]], [[Pope Innocent XI]] made him [[Apostolic Vicariate of Northern Germany#Vicars Apostolic for the Nordic Missions|Vicar Apostolic for the Nordic Missions]] on 21 August 1677. He was consecrated [[bishop of Titiopolis|titular bishop of Titiopolis]] on 19 September by [[Gregorio Barbarigo|Cardinal Gregorio Barbarigo]] and moved to the Lutheran North.{{sfnp|Miniati|2009|loc=Note 26, page 77.}}

In the year after he was made bishop, he was probably involved in the banning of publications by [[Baruch Spinoza]],.{{sfnp|Israel|2002|pp=251, 316}} There he had talks with [[Gottfried Leibniz]], the librarian; the two argued about Spinoza and his letter to [[Albert Burgh]], then Steensen's pupil.<ref>{{cite web |url=http://www.skepticfiles.org/atheist/spinozad.htm |title=Skeptic files website |publisher=Skepticfiles.org |access-date=11 January 2012 |archive-url=https://web.archive.org/web/20131107063338/http://www.skepticfiles.org/atheist/spinozad.htm |archive-date=7 November 2013 |url-status=dead }}</ref> Leibniz recommended a reunification of the churches. Steensen worked at the city of [[Hannover]] until 1680.

After John Frederick death's, [[Prince-Bishop of Paderborn]] [[Ferdinand von Fürstenberg (1626–1683)|Ferdinand of Fürstenberg]] appointed him as Auxiliary [[Bishop of Münster]] (Church Saint Liudger) on 7 October 1680.{{sfnp|Scherz|2002}} The new [[prince-elector]] [[Ernest Augustus, Elector of Hanover]] was a Protestant. Earlier, Augustus' wife, [[Sophia of Hanover]], had made fun of Steensen's piousness; he had sold his bishop's ring and cross to help the needy.{{Citation needed|date=January 2012}} He continued zealously the work of counter reform begun by [[Bernhard von Galen]].{{sfnp|Scherz|2002}}