D(ominus) Iohan(nes) Iessenius a Iessen olim Vitenberg, nunc Carolinae Prag(ae) Acad(emiae) rector purpuratus. A contemporary copperplate by Matthäus Merian, 1617
He was from an old noble family, the House of Jeszenszky, originally from the Kingdom of Hungary. He presented himself in his own works as eques Ungarus ("Hungarian knight").[1] According to scholar publications, he had Slovak,[2][3][4]Polish or German[1] roots. His father, Boldizsár Jeszenszky de Nagyjeszen, left Turóc County (today the Turiec region in Slovakia) because of the Ottomans' military campaign against Upper Hungary and settled down in Silesia in 1555. He married Marta Schülerin, who came from a wealthy German bourgeois family.[5]
In 1600 he attracted considerable public interest by performing a public autopsy in Prague. (His notes on the autopsy were published in 2005 by Karolinum, a publishing house of Charles University of Prague.)[6]
In 1618, Jesenius was arrested in Pressburg (Bratislava) after being sent as a deputy by the Bohemian estates, and was held in a prison of Vienna. In December, he was released in exchange for two Habsburg captives. There is a legend that, before his release, he wrote the inscription IMMMM on the wall of his prison cell. Ferdinand explained this as Imperator Mathias Mense Martio Morietur (Latin for "Emperor Mathias will die in the month of March"), and he wrote another prophecy next to it: Iesseni, Mentiris, Mala Morte Morieris ("Jesenius, you lie, you will die a horrible death").
Jesenius was honored during the 450th anniversary of his birth (2016) by a postage stamp jointly issued by Hungary, Czech Republic, Poland, & Slovakia.[7]
