RR-, Sigismund I the Old, Grosz 1555, Gdansk/Królewiec, period forgery, rare

A very rare type of forgery from the period. Mistaken and abbreviated date 55 (instead of 1535), on the reverse the coat of arms of Danzig, however, from the rim on both obverse and reverse at 12 o'clock the Hohenzollern coat of arms, which may suggest a forgery workshop from Königsberg. The shape of the letters quite correct, but the legends confused and some of the letters reversed.