1659-1664. Green route: the trip to the Netherlands
In the winter of 1659-60 when the Karl Gustav Wars between Denmark and Sweden had ended, Niels Steensen embarked on his first journey abroad. He travelled by way of Rostock to Amsterdam to study. Amsterdam was a great centre of research, industry and trade—five times the size of Copenhagen.
In Amsterdam he stayed with and studied under Gerard Blasius. While studying with Blasius, Steensen made his first great discovery, that of the ductus stenonianus.
In July 1660 Steensen travelled by barge to Leiden and registered as a student at Leiden University. He was joined there by his former teacher Ole Borch. Steensen spent more than three years at Leiden University where he made important discoveries concerning the glands, muscles and heart. He followed the anatomy lectures of Francois de la Boë Sylvius, and made the acquaintance of prominent scientists and doctors of medicine and the philosopher Spinoza. He wrote and defended his dissertation of the glands of the mouth. He most likely followed a dissection at the Anatomical theatre and used the University Library.
In 1663 he went on holiday, travelling in the Netherlands and Belgium with Ole Borch and his charges. They could not have missed seeing Leuven’s famous town hall. While there they witnessed a Corpus Christi procession.
In 1664 Niels Steensen ran out of money so he went back at home to Copenhagen where published his new book, “Anatomical observations”.