This is a genuine Spanish silver coin minted in Mexico City during the reign of Charles I and Johanna “The Mad.” Coins struck in this early colonial period are among the first ever minted in the New World. The obverse features the crowned heraldic shield of León and Castile, with a castle and lion alternating in four quadrants, and a pomegranate at the base. On either side is the Mexico mintmark “M”. The legend includes a variation of “CAROLVS ET IOHANA REGES” (Charles and Johanna rulers).
The reverse shows the crowned Pillars of Hercules emerging from the sea, representing the Strait of Gibraltar. Between the pillars is a banner with the motto PLUS ULTRA ("more beyond"), referencing Spain’s reach into the New World. On smaller denominations, the legends are often abbreviated. The phrase “HISPANIARVM ET INDIARVM” (“of the Spains and the Indies”) acknowledges the multiple kingdoms that then formed Spain.