A "unique" medieval coin from the reign of William the Conqueror has been discovered in a field near Gloucester.
The hammered silver coin was found by metal detectorist Maureen Jones just north of the city in November.
Experts from the Portable Antiquities Scheme said the find "filled in the hole" in the dates the Gloucester mint was known to have been operating.
The coin, which dates from 1077-1080, features the name of the moneyer Silacwine and where it was minted.
The Portable Antiquities Scheme said that until the coin was discovered, there were no known examples of William I coins minted in Gloucester between 1077-1080.
"The discovery of this coin therefore proves that the mint was in operation throughout the whole reign of William I," it said.
Ms Jones, who found the coin, is a member of Taynton Metal Detecting Club.
"I went out with two other ladies to an open field and that's where I found it," she said.
"I know it's a silver hammered coin but I didn't recognise the king.
"It's quite amazing."
Kurt Adams, finds liaison officer for the Portable Antiquities Scheme, said the penny coin would have been "quite valuable" at the time that it is thought to been lost by its owner more than 900 years ago.
It is due to be returned to Ms Jones shortly.