A painting thought to be a copy of work done by British artist George Stubbs has been found to be the original.
The work of art was put on sale for $5,000 (£4,050) by a library in California.
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However, an art dealer from Chelsea, London, believed the painting may have been real.
Archie Parker said: "I came across a Chirstie's catalogue for an interiors sale and within it, among mostly furniture, was this painting."
The painting actually includes a visible signature in the bottom right corner, as well as a date and light pencil markings that show the first draft of the picture.
It turned out that Archie Parker's suspicions were in fact correct - the painting was real.
After buying the painting for $20,000 (£16,200) he is now selling it on for a sizable profit.
He says: "If the highest bid had been $50 (£40), that's what it would have been sold for. For a while it was about to go down at $5,000, before the telephones came in.
"It went up to $175,000 (£141,600) which, including buyer's premium, was just over $200,000 (£161,900)."