It’s a mystery worthy of Sherlock Holmes himself - who, and what, inspired Sir Arthur Conan Doyle's classic novel, 'The Hound of the Baskervilles'?
In their most celebrated case, Holmes and Watson investigate the curse of a gruesome beast terrorising the Baskerville family.
The story is set on Dartmoor in Devon, but the real life Baskervilles owned a country mansion in Wales, often visited by Conan Doyle himself.
In fact, he knew the family well.
In the ITV series “Wonders of the Border”, Sean Fletcher follows the trail to the village of Clyro, on the edge of the Brecon Beacons National Park.
The local pub is called the Baskerville Arms, and a memorial in the churchyard is inscribed with the Baskerville name.
At the entrance to the village stands Baskerville Hall itself - a hotel that was once the grand family home of the Baskervilles.
Its current owner, David Hodby, is convinced that it was Powys, not Devon, where the seeds of the story were first sown.
“Conan Doyle visited here and was a family friend,” he explains. “He would have gone out shooting with them, enjoying life in the countryside with them. He asked permission of the Baskervilles to use the family’s history of the house and grounds in the story.
“They were a noble family and they didn’t want Conan Doyle writing stories in the newspapers in London. But Conan Doyle enjoyed walking all over the country. He knew the Lake District, the Peak District, the Brecon Beacons and Dartmoor. So it was easy enough for him to set it on Dartmoor instead”.
Eurwyn Jones, from Sherlock Holmes society the Deerstalkers of Welshpool, has unearthed further clues linking mid Wales to Conan Doyle’s masterpiece.
In the novel, Sir Charles Baskerville dies of a heart attack when he encounters the hound in a wooded area near the Hall: Yew Alley. The real life Baskerville Hall has an alley of yew trees that mirror the novel’s description.
Inside the mansion, the grand staircase perfectly matches a passage in the novel which reads: “A square balustraded gallery ran round the top of the old hall, approached by a double stair.”
But perhaps the most intriguing clue is a legal document from 1907.
The paperwork relates to the sale of two farms to Ralph Hopton Baskerville. There are two signatures clearly visible on the document: RH Baskerville and Arthur Conan Doyle. Conan Doyle himself owned land in the area and his first wife also had strong links to Wales.
For Eurwyn Jones, the case is closed: “There are many places that lay a claim to being the inspiration for this book, but for me there’s no more compelling evidence than this document and this building. It’s elementary!".
You can see more on this story in Wonders of the Border, tonight at 7:30pm on ITV Cymru Wales.
The episode can then be streamed online at: itv.com/walesprogrammes