The impact of Leiden-educated Niels Stensen (Nicolas Steno) on the advancement of medical knowledge and practices

Danish polymath Niels Stensen journeyed to the Dutch Republic (1660) to further his medical studies. While staying with Blasius in Amsterdam, he made an important discovery in the anatomy of the parotid duct: the <i>ductus Stenonianus</i>. Blasius later took credit, leading to a dispute won by Stensen. Realising he could learn little in Amsterdam, Stensen moved to Leiden University (July 1660). Here, he studied under renowned professors Sylvius and van Horne and became friends with talented fellow students Swammerdam, Ruysch, and de Graaf, who significantly contributed to anatomy and reproductive medicine. Stensen discovered various anatomical and physiological aspects, leading to his doctorate from Leiden. Here, he met Spinoza and maintained correspondence with him. Stensen left Leiden (1664), spending time in Paris, and moved to Florence (1666), joining the <i>Accademia del Cimento</i>. His interests expanded from anatomy to geology; he converted to Catholicism (1667), was ordained as a priest (1675) and became bishop. His ecclesiastical duties took him to Germany, where he lived a life of asceticism, dying in 1686. His remains were moved to Florence and buried in the Basilica of San Lorenzo. Stensen's journey reflects a commitment to knowledge and spirituality, making him a figure of intellectual and religious significance.