A detectorist has uncovered just the eighth known example of England’s “first gold coinage”, with the piece expected to sell at auction for nearly half a million pounds.
The Henry III coin, minted in 1257, owes its value both to its rarity and the unique portrait of the monarch on its obverse side.
The coin carries a pre-sale estimate of £400,000 but past examples have sold for more than £500,000. It is the first of its kind found in more than 260 years.
It was found by an anonymous treasure hunter on his first detecting trip in a decade, near Hemyock, Devon.
Watch: Furloughed Londoner finds fortune in the Thames
The finder put it on Facebook, not knowing its true value before it was spotted by an expert.
Gregory Edmund, of the auctioneer Spink, told The Telegraph he spotted the post and “immediately told the finder to take it down because I said you're going to be inundated with every man and his dog to try trying to buy this off you for a fraction of what it's worth”.
Mr Edmund and the detectorist took the coin to be assessed by the British Museum, which confirmed its significance. As it is only a single coin and not part of a larger find, it was not covered by the Treasurers Act, meaning the finder was entitled to keep it.
The coin has since been offered up to academics for study, including a non-invasive X-ray fluorescence test that confirmed its gold content. It will now go up for auction on January 23.
The coin was the first gold coin minted in England since before the Norman Conquest. However, it proved deeply unpopular and of little wider use.
Henry III, who ordered the coins to be minted, had originally been saving gold for a campaign to place his son on the throne of the Kingdom of Sicily.
However, the growing threat of Llywelyn ap Gruffudd, the last Welsh Prince of Wales, led Henry to instead use his personal treasure to fund an expensive military campaign across Offa’s Dyke.
Its use by the King to pay his many bills and creditors may explain why this example ended up in Devon.
Prof David Carpenter, a leading medievalist at King’s College London, has traced the coin to John de Hidon, the lord of Hemyock Manor. It may have fallen from the pocket of de Hidon himself, or one of his labourers, said the professor.
While the coin allowed Henry III to successfully wage war against Llewelyn, it proved deeply unpopular, both with goldsmiths in London and with the wider population.
The flood of coins into the economy caused the value of gold to sink, despite the coin itself having a fixed value.
It was also worth around two weeks of the average worker’s wage, a sum that was likely too large to be practical.
The portrait of Henry III on the coin’s obverse was “radically new” according to Prof Carpenter. Rather than simply showing the head of the king, it depicted him “sitting elegantly on his throne” with his sceptre and orb.
While unlikely to have been understood by his subjects, it was an attempt by Henry III to model himself on his patron saint, Edward the Confessor.
The coin also shows cross-hatched ground before his feet, which may hint at the Cosmati floor he had constructed at Westminster Abbey a decade later. “This provides us with the tantalising prospect that this coin is Henry III’s vision for Westminster Abbey,” said Prof Carpenter.
Of the other seven known coins, four are in museums, including one in the British Museum, with one on display from a private collection and three not visible to the public.
Watch: US coin sells for record $19.5 million at Sotheby's auction