The first guinea was struck in 1663. It marked a shift from the coins issued during Cromwell’s short-lived republic to a more impressive coinage bearing the portrait of the newly restored king, Charles II. The gold guinea was undoubtedly the major British coin of the eighteenth century before production came to an end in 1813. The last batch was struck to pay the Duke of Wellington’s army in the Pyrenees, an issue that became known as the Military Guinea.
Initially, Guinea was not the official name of the coin. It acquired this moniker because of the origin of the gold used to produce the first pieces – the Guinea Coast of Africa. It was given a nominal value of 20 shillings, but was subject to fluctuations as the price of gold increased. Finally, in 1717, it was set at 21 shillings, a monetary unit that survives to the present day – horses are still sold in guineas.