"The original story goes that Robert Plant found the painting in a second-hand store in Reading, Berkshire, while on his way to recording sessions at Headley Grange in Hampshire. Some have claimed that the old man is Henry "Brusher" Mills, a well-known Victorian-era snake catcher who lived in Hampshire's New Forest, while Jimmy Page reportedly noted the figure's resemblance to ‘Old George’ Pickingill – who had first instructed Aleister Crowley in the occult – and made the painting a feature of the cover art. Typically, Page has been reluctant to provide further detail.

"‘The cover was supposed to be something that was for other people to savour rather than for me to actually spell everything out," he told The Times in 2010. "Which would make the whole thing rather disappointing on that level of your own personal adventure into the music."

Now the mystery has been solved, after the original photograph on which the painting was based was found during research for an upcoming exhibition at the Wiltshire Museum in Devizes. The picture was discovered in an old album by Brian Edwards, a Visiting Research Fellow with the Regional History Centre at the University of the West of England, who, being a Led Zeppelin fan, recognised the image immediately.

"Led Zeppelin created the soundtrack that has accompanied me since my teenage years," says Edwards. "So I really hope the discovery of this Victorian photograph pleases and entertains Robert, Jimmy, and John Paul."

Further research was able to able to suggest likely candidates for both the photographer and his subject. A part signature matching the writing in the album suggests the man behind the camera was photography teacher Ernest Howard Farmer (1856-1944), while the stooped figure is likely to be Lot Long – also known as Lot Longyear – a thatcher (a craftsman who installs traditional thatched roofing), from the small town of Mere in southwest Wiltshire. Lot was born in 1823 and died in 1893."

- Fraser Lewry/LOUDER