During the reign of Sigismund the Old, in 1526-1528, perhaps the most important monetary reform in the history of Polish money was carried out. A modern, well-functioning system based on full value coinage - silver and gold - was introduced. The monetary system of Sigismund the Old was represented by denars, ternars, shekels, half-pennies, groszy, troyaks, sixpences, thalers (still medals) and ducats. The king led to the monetary union of the Crown and Royal Prussia. However, the monetary system of the Grand Duchy of Lithuania functioned separately (4 Lithuanian pennies equaled 5 Polish pennies). Sigismund the Old left his mark not only on Polish minting (as King of Poland) and on Lithuanian minting (as Grand Duke of Lithuania). He also left his mark in Silesian minting as Duke of Glogow, minting (possibly) halerds and (certainly) Glogow groshes in 1505 and 1506.
Sigismund the Old's crown half-pennies of 1507 are the first Polish (in the strict sense of the word) dated coins. They were minted at the Cracow mint on the basis of the ordinance of 1507, from sterling silver, weighed an average of 1.029 g and contained 0.386 g of pure bullion. On the obverse of crown half-pennies were placed a crown and an otolith inscription with the date. On the reverse side was the White Eagle and an otolith inscription. They were issued in 1507-1511. Lithuanian half-pennies were minted at the Vilnius mint in 1508-1529, for the Lithuanian foot. Their ratio to the crown half-pennies was 4 : 5. They were minted from sterling silver, weighed an average of 1.287 g and contained 0.482 g of pure silver. On their obverse was placed the coat of arms of Lithuania - the Coat of Arms and an otolith inscription (with the date). On the reverse - the White Eagle and the otolith inscription.
