What do the symbols on a piece of eight mean?

The term "Pieces of Eight" refers to all Spanish silver coins that were minted during the 16th, 17th, and 18th centuries. The primary denomination, 8 Reales, was equal to one troy ounce of silver. Each had a value of about one month's wages for a sailor in the 1600s. Each coin was hand made and hand cut to achieve desired weight, making each piece one-of-kind in its shape and beauty. Coin enthusiasts may enjoy "Treasure Coins of the Nuestra Senora de Atocha & the Santa Margarita book, by Carol Tedesco" with a special section devoted to the exceedingly rare Old World minted coins discovered on the Atocha and the Santa Margarita.