On February 9, 2023, the National Bank of Poland is launching a collector's banknote with the denomination of PLN 20, "Nicolaus Copernicus." This is the second collector polymer banknote issued by the NBP. The front side of the banknote depicts the most popular (so-called Torun) portrait of Nicolaus Copernicus, as well as stylized images of the quadrant and a fragment of the heliocentric system. The reverse side of the banknote features images of historical coins: the obverse and reverse of the Danzig sixpence, the obverse of the Elbląg sixpence, the obverse of the Prussian shekel (Toruń), as well as an image of a fragment of the heliocentric system. Also visible in the background is the Castle of the Warmian Chapter in Olsztyn. The fragment of the image of the heliocentric system was taken from the manuscript of Nicolaus Copernicus' treatise On the Revolutions of the Celestial Spheres, located in the Jagiellonian Library. The year 2023 marks the 550th anniversary of the birth of Nicolaus Copernicus, an eminent astronomer, creator of the heliocentric theory, physician, economist - author of one version of the law governing the circulation of money (inferior money always displaces superior), faithful subject of Polish kings - defender of Olsztyn against the Teutonic Knights.