When Janusz Parchimowicz published a specialized catalog for the coins of the First Republic of Poland, the biggest surprise and the section that aroused admiration was the section describing unknown stamps from the collection of the Numismatic Cabinet of the Mint of Poland, which were found by the author in the aforementioned cabinet during a search in 2010. A year later, a limited edition series based on images of the unknown stamps was minted at the Warsaw Mint.