Guinea

British gold coin with a nominal value of £1 (twenty shillings), first issued in 1663 and named after gold from Guinea in West Africa ‘in the name and for the use of the Company of Royal Adventurers of England trading with Africa’. 

George III 'Spade' Guinea,
1798, so-called because of
the distinctive spade-
shaped shield on the
reverse (Credit: Spink
& Son Ltd)

The coin was unofficially revalued at £1.1.0 d (twenty-one shillings) at the recoinage of 1696, a value confirmed in 1717. The Guinea became the legal tender coin circulating for the next one hundred years and symbolized Britain’s shift to the gold standard.

Payments in Guineas were largely replaced by notes during the Napoleonic wars; the last was minted in 1813 and in 1817 it was replaced by the Sovereign containing slightly less gold and valued at £1.