The first escudo was a gold coin introduced in 1535/1537, with coins denominated in escudos issued until 1833. It was initially worth 16 reales When different reales were introduced, the escudo became worth 16 reales de plata in 1642, then 16 reales de plata fuerte or 40 reales de vellón from 1737.
Gold coins were issued in denominations of ½, 1, 2, 4 and 8 escudos, with the 2 escudos coin known as the doubloon. Between 1809 and 1849, coins denominated as 80, 160 and 320 reales (de vellon) were issued, equivalent, in gold content and value, to the 2, 4 and 8 escudo coins.
Most were minted in Madrid, marked with a superscripted M or in Seville bearing an S below and left of the Royal Coat of Arms. The mintmaster’s initials appeared on the opposite side.