Florin (English coin)
The double florin or double leopard was an attempt in 1344 by English king Edward III to produce a gold coinage suitable for use in Europe as well as in England (see also florin or leopard and half florin or helm). It was 108 grains (6.99829 grams) of nominal pure ('fine') gold and had a value of six shillings (i.e. 72 pence). 
The continental florin, based on a French coin and ultimately on coins issued in Florence, Italy, in 1252, was a standard coin (3.5 g fine gold) widely used internationally.
The coins were underweight for their value, resulting in them being unacceptable to merchants, and the coins were withdrawn after only a few months in circulation, in August 1344, to be melted down to produce the more popular gold noble (9 g gold valued at 6s 8d).
The obverse of the coin shows the King enthroned beneath a canopy, with two leopards' heads at the sides (the leopard being the heraldic "lion" on the English coat of arms); the legend is EDWR D GRA REX ANGL ⁊ FRANC DNS HIB ("Edward, by the Grace of God King of England and France, Lord of Ireland"). The reverse of the coin shows the Royal cross within a quatrefoil, a leopard in each spandrel; the legend is IHC TRANSIENS PER MEDIUM ILLORUM IBAT ("But Jesus passing through their midst went his way", from Luke 4:30).
Only three examples of this coin are known to exist: two discovered in the River Tyne in 1857, and one discovered in January 2006. The latter coin was sold at auction in July 2006 for a record price for a British coin, of £460,000. The first two discovered are displayed in the British Museum. It is currently valued at $6.8 million.
- Great Britain Royal Mint (1906). Catalogue of the Coins, Tokens, Medals, Dies, and Seals in the Museum of the Royal Mint (volume 1 ed.). H.M. Stationery Office. p. 40. Retrieved 23 March 2016.
- Emma Howard (August 2018). Coins of England & the United Kingdom 2018: Predecimal Issues. Spink. ISBN 978-1-907427-63-3.
- Spink, Coins of England and the United Kingdom. 46th edition standard catalogue of British coins, 2011.
- "News – The Scotsman". Scotsman.com. Retrieved 21 March 2019.
- "The 10 Most Expensive Coins and Banknotes in the World". mentalfloss.com. 2013-11-12. Retrieved 2019-05-01.
- Picture of double leopard and noble on www.ukcoinpics.co.uk