Very rare issue from the reign of Sigismund II Augustus.
Silver half ducat of the Kingdom of Naples of Philip II, from 1556-1571, with a countermark with the monogram of Sigismund II Augustus, dated 1564.
Coin that is a repayment of the so-called Neapolitan Sum.
The royal countermark was probably minted in the Vilnius or Tykocin mint, which makes it a desirable and sought-after issue by Polish and Lithuanian collectors.
Obverse: bust of Emperor Philip II facing right
PHILIPP R ARAGON VTRIV
Reverse: crowned, multi-field coat of arms, with a countermark with the monogram SA (Sigismundus Augustus), of the Polish king Sigismund II Augustus
SICIL ET HIERVSAL
Diameter 35 mm