This is the only gold coin in the collections of the Royal Castle in Warsaw from the so-called royal series—consisting of 23 pieces—belonging to King Stanisław August Poniatowski. It was acquired for the Castle’s collection through a foreign purchase in 1987. It was made during the King’s lifetime—the originator of the series—after 1792 by the engraver Jan Jakub Reichl, who continued the work begun by Jan Filip Holzhaeusser. The coins in the series were struck in three metals—gold (only one or perhaps two copies), silver and bronze. Almost the entire series of gold coins (originally housed in the Lyceum at Krzemieniec (now Kremenets, Ukraine) is now part of the collection of the Historical Museum of Ukraine in Kiev. Similarly to the other coins in the series, the design for the King’s portrait on the obverse was modelled on the portrait painted by Marcello Bacciarelli, hung in the Marble Room at the Royal Castle in Warsaw. The inscription on the reverse glorifies and describes the first ruler of the Vasa dynasty. Following King Stanislaw August’s suggestion, the inscription—just like the image itself—was also taken from the reverse of the painting. The inscription may have been by one of the scholars in the royal circle, e.g. Adam Naruszewicz.