A nice piece of a typologically more interesting item.
Patina, tarnish.
Obverse: royal bust wearing a laurel wreath with double bindings, wearing armor with 5 buttons in a row on the epaulet and a mascaron on the breastplate, to the right, under the bust the initials T.L.B. Titus Livius Boratini, in the rim the legend:
IOAN III D-G-REX POL-M D-L-R-P-;
Reverse: crowned with a four-cornered crown with five rosette fleurons, with 4 jewels in the rim with 12 jewels on the bails, a three-field escutcheon, with the coats of arms of the Crown, the Grand Duchy of Lithuania and the Sobieski family coat of arms - Janina without decorations; under the crown the denomination mark VI, under the escutcheon the date 16-81; in the rim the legend punctuated by the Leliwa coat of arms in an oval escutcheon:
GROS-ARG-SEX-REG-POLONIAE;