A painting of the Virgin Mary, believed to be a copy, was sold in 1899 for $25.
Now, a team of experts says the painting may be a genuine Raphael worth $26 million.
Bendor Grosvenor, an art historian, made the discovery while he and a team of experts were examining the collection at the National Trust for Scotland's Haddo House collection in Aberdeenshire, according to CNN.
Grosvenor said the Madonna painting really caught his eye.
"I thought, crikey, it looks like a Raphael," Grosvenor told The Guardian. "It was very dirty under old varnish, which goes yellow Being an anorak, I go round houses like this with binoculars and torches. If I hadn't done that, I'd probably have walked past it."
He later discovered that the picture had been purchased as a Raphael in the early 19th century and was exhibited alongside other Raphaels.
Not long after, the painting was attributed to a minor Renaissance artist, Innocenzo Francucci da Imola.
Grosvenor, however, wasn't convinced.
"It is simply too good to be by Innocenzo," he said.
He asked permission to have the piece professionally cleaned, conserved and investigated after noticing its resemblance to the Italian painter's work. original creative intervention, meaning the picture cannot be a copy of another known work.
Grosvenor told The Guardian an alteration on one of the fingers "suggests an original creative intervention, meaning the picture cannot be a copy of another known work."
The piece is still credited to Imola on the Art UK database, but Grosvenor said all the evidence so far seems to point in the right direction.
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