These machine-produced silver coins, each with a value of 8 reales, were part of the Spanish currency system during the Bourbon period. The system was reformed by Charles III in 1772 and was in place during the reigns of Charles III and Charles IV.
These particular coins are from the frigate "Nuestra Señora de las Mercedes," which sank in 1804 following the attack at Cape Santa Maria by an English fleet. The frigate was traveling to Spain, carrying treasure from the viceroyalties, meaning that these coins were made in the mints of Spain's overseas territories. Most of them were coined in Lima in 1803 and 1804, while smaller a number of them were coined in Potosí. They also include some 2- and 4-real coins. The fragments of textile found, and the shape of some of the blocks of coins, reveal that the coins were transported in cloth bags and wooden chests.
Many of the coins that were found in the wreck were mechanically manufactured using a coining press, producing perfect circles with engraved edges. They feature the King's image on the obverse, along with an inscription and a smooth line around the entire face. The back of the coin has the same composition, except that it features a crowned shield flanked by 2 Hercules columns and the motto ''PLVS VLTRA.''