A teacher who pulled a sword from a sandy area in a cave more than 30 years ago has discovered it could date back to the 13th Century.
Mark Lawton spotted the sword "sticking out of the sand" while walking through Shropshire's Caynton caves in 1985.
Since then, it has been kept on his windowsill at his home in Wombourne.
Mr Lawton said he "always wondered about its age" and sent it to a specialist who said it could have belonged to a medieval knight.
"We were walking towards the bottom end of the cave; it doesn't really go anywhere and it was pitch black when we saw something sticking out of the sand.
"I pulled it and out came the sword."
Caroline Dennard, a specialist from Halls Fine Art Auctioneers in Shrewsbury identified the sword as possibly being from the 13th century.
"Stylistically it's very in line with other swords I've seen," she said although said it would have to be tested to make sure it is not a replica made in the Victorian era.
She said there is debate about when the man made caves were built, with some suggesting it was not until the 1800s and this find could add to the mystery.
Finding a medieval sword is rare, she said, because most swords dropped in muddy battlefields would degrade over about 30 years.
Mr Lawton is getting the sword tested by experts at Shropshire Council and the British Museum, and believes it could fetch up to £1,500 if it's found to be authentic.
"I probably would sell it," he said. "My wife has always had a bad feeling about it."
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