The painting, on a 100 centimeter by 80 centimeter (40x31 inch) canvas, was bought by the Kroeller-Mueller Museum in 1974 as a Van Gogh. The work was thought to come from the artist's period living with his brother Theo in Paris from late 1886.

Experts thought the canvas was too large for that period, the depiction of a vase brimming over with flowers and yet more flowers lying on a table in the foreground was too exuberant, too busy. The signature was in an unusual position for Van Gogh — the top right hand corner.

With the doubts piling up, the museum in 2003 decided to attribute the painting to an anonymous artist instead of to Van Gogh.

But the detective work did not end there.

An X-ray taken five years earlier had already revealed an indistinct image of the wrestlers and continued to interest researchers.

Now, a new more detailed X-ray has shown the wrestlers in more detail, along with the brush strokes and pigments used. They all pointed back to Van Gogh.

Having models pose half naked was a defining characteristic of the Antwerp academy where Van Gogh studied in early 1886. So was the size of the canvas, the Kroeller-Mueller Museum said in a statement.

Vincent wrote to his brother about needing the large canvas, new brushes and paint. Theo helped the penniless artist buy the materials and a week later Van Gogh wrote back that he was delighted with the painting of two wrestlers.

Brush strokes and pigments in the wrestlers painting also corresponded with what experts now know about Van Gogh's work in Antwerp.

The wrestlers also help explain the "uncharacteristic exuberance" of the floral still life, the Kroeller-Mueller Museum statement said — Van Gogh had to cover up all of the old image with his new work.