This unique new release from the British Royal Mint celebrates the "Gold Standard" monetary system wherein the value of a country's money is tied to the amount of gold the country possesses. Anyone holding that country's paper money could present it to the government and receive an agreed value (par value) from the country's gold reserves.
The Gold Standard was established in 1816 by the Coinage Act, which defined the value of gold sterling relative to gold. Britain led the way and was the first country in the modern era to adopt the standard. Other European and Western countries soon followed. Up until the First World War, the Gold Standard encouraged stability in prices, and has the Queen Elizabeth II on the reverse.