Jan Jesenius

Jan Jesenius, also written as Jessenius (, , ; 27 December 1566 – 21 June 1621), was a Bohemian physician, anatomist, politician and philosopher. He was active in Prague, where he gained fame after he conducted a public dissection of a human body for scientific purposes. He was publicly executed following the Battle of White Mountain.

Life Early years Jesenius was from an old noble family, the Jeszenszky family, originally from the Kingdom of Hungary. His father Boldizsár (Baltazar) Jeszenszky de Nagyjeszen was from Turóc County (today the Turiec region in Slovakia) and had settled in Breslau (today Wrocław, Poland) around 1555 following the Ottoman campaign in Upper Hungary. He worked as a diplomat and was married to Martha Schiller who was of German origin. He presented himself in his own works as eques Ungarus ("Hungarian knight"). Polish or German roots.

Jan Jesenius was born in Breslau in Bohemia, where he studied at the Elisabeth gymnasium. From 1583, he studied philosophy and medicine at the University of Wittenberg, from 1585 at the University of Leipzig, where he conducted vivisection of a cat under the anatomist Georg Walther. He received a bachelors degree with a dissertation titled De animae humanae immortalitate (On the Immortality of the Human Soul) in 1587. From 1588 he was at the University of Padua where he was taught by Girolamo Fabrizio. In 1591 he defended his medical thesis De Putrescentis Bilis in Febre Tertiana Exquisita Intermittente Loco (On the role of Putrifying Bile in Acquired Malaria Tertiana) and another in philosophy Pro vindiciis contra tyrannos (For the Defence Against Tyrants). As a protestant he was not eligible for the degree by the Catholic university of Padua but recommendations from his professors allowed him to obtain one. He returned to Breslau where he worked as a physician. thumb leftHe married Maria Fels, daughter of the Imperial Registrar of the Silesian Chamber, Adamus Fels Sr, in 1595. She died in 1612 in Sopron, Hungary. In 1601 he was among the first to consider the idea of skin diseases and their origins in his De cute, et cutaneis affectibus. During the 1606 plague he wrote De cavenda peste (On Evading the Plague) and in 1608 he wrote De sanguine, vena secta dimisso, iudicium (Treatise on Blood and Blood-Letting).

In 1617, he was elected rector of Charles University in Prague. He was forced to resign the position in 1620.

Emperor Mathias died in March 1619, and Jesenius was arrested after the defeat of King Frederick of Bohemia by Emperor Ferdinand II in 1620 (Battle of White Mountain) and executed, along with 26 other Bohemian estates leaders, on the Old Town Square in 1621. The committee that interrogated him came to the verdict "ex gratia imperalia his tongue will be cut out alive, then he will be beheaded and quadrisected and hung at a crossroads close to the scaffold; his head with his tongue will be placed at the bridge" and after the execution his head was displayed on the Old Tower bridge along with eleven others.