A nice piece. Variety without inner surround on the reverse.
First vintage of trojaks minted in Gdansk during the reign of Sigismund Augustus.
Obverse: inscription in four lines:
+III+/GROS○AR/TRIP○CIVI/GEDANEN; below, punctuated by a Polish-type shield with the coat of arms of Gdańsk, the date: +15=57+;
Reverse: royal bust in crown and plate armor, to the right, surrounded by legend:
SIGIS○AVG○REX○PO○D○PRVS;