A nice piece with fairly well-preserved details.
Obverse: denomination III between stars, below it the coat of arms of Riga, separating the dates 15-85 and the beginning of the legend GR-OS, below it further 3 lines of the legend:
ARG-TRIP/CIVI-RI/-GE-;
Reverse: crowned royal bust with numerous jewels in crown rim, wearing plate armor, to the right, in the rim legend:
STEP-D-G-REX-P-D-L-;