Nice piece with some residual luster
Obverse: in a pearl rim a royal bust wearing a crown, armor and cloak studded with jewels, with the Order of the Golden Fleece, to the right, in the outer rim a legend:
IOAN CASIMI D G REX POL & SVG M D R P;
Reverse: in a pearl rim crowned with a five-pointed crown with 9 jewels in an open rim, with 5 rosette fleurons, a five-pointed decorative shield with the coats of arms of the Crown, the Grand Duchy of Lithuania and the coat of arms of the Snopes of the Vasa dynasty, sides denomination mark 1-8 and initials A-T, in the outer rim the legend punctuated by the Wieniawa coat of arms in the Shield:
COIN NOVA RE-GNI POLON 1658;