Grosz koronny / Z MIEDZI KRAIOWEY / - Stanisław August Poniatowski Warszawa mint

The inscription Z MIEDZI KRAIOWEY — "from domestic copper" — was not decorative patriotism. It was a direct response to decades of foreign minting contracts and the chronic outflow of raw metal that had bled Polish coinage since the Saxon era. Poniatowski's monetary reforms of the 1760s–80s were an attempt to reassert control over a monetary system that had been exploited, debased, and partly farmed out to outside interests for generations.

The three Kopernik references correspond to the 1786, 1787, and 1788 dated varieties respectively, each with minor die differences.