(UPI) — A Nicolas de Largilliere painting that was stolen from a Jewish collector by the Nazis during World War II is scheduled to go to auction on Thursday after it was recovered by his heirs.

Portrait of a Lady as Pomona — a piece by the French painter depicting Marquise de Paraber as Pomona, goddess of fruit and abundance — will be put up for sale at Sotheby’s in New York City following the lengthy journey to return the painting to the heirs of collector Jules Strauss.

Strauss, a German member of the Jewish faith who lives in France, had amassed a collection of more than 150 paintings by Dutch and Flemish Masters and other impressionists. Many works from his collections were sold at auctions in Paris in 1902 and 1932 and can be found in principal museum collections throughout the world.

However, in 2014, his great-granddaughter, Pauline Baer de Perignon, said she ran into her art dealer cousin at a concert and he told her that Strauss may have been robbed.

“I was in shock,” Baer de Perignon told the New York Post, adding that the news was like “hearing so much information that your brain stops working properly because it’s just so big.”

She later learned that Strauss and his family were forced to leave their home after the Nazis requisitioned it as France surrendered to Germany in 1940 — and that a German task force seized a storage unit belonging to the family two years later. It contained 68 crates filled with furniture and paintings.

Baer de Perignon, while searching a list of claims made to the French Looted Art Commission at the Looted Art Archives outside of Paris, found the name of her great-grandmother, Marie-Louise Strauss.

“When I saw the file with the handwriting of my great-grandmother — that’s when I knew that she had been looted, that something happened,” she said. “It made me shiver.”

She later found 600 documents in the German Federal Archives containing her grandmother Elisabeth’s claims from 1958 to 1974 against the German government, which ruled that the family hadn’t provided enough evidence to show the works had been stolen or sent to Germany.

Baer de Perignon eventually tracked down the Portrait of a Lady as Pomona, which had been in the collection of the Gemaldeggalerie Alte Meister Staatliche Kunstasmmlungen from 1959 until early 2021.

“I said, ‘OK, [the museum] knows it’s looted,” Baer de Perignon said, according to the Post. “I was a bit naive … That was the beginning of years of conversations where I had to prove all that time that it belonged to my great grandfather and it had been taken.”

She combed through Strauss’ journals for evidence that he owned the painting and that the sale was forced, but continued to face resistance from the museum.

The museum eventually released the painting to the family after Baer de Perignon hired an attorney specializing in art restitution to compile a dossier, proving the forced sale to end a lengthy legal battle in Germany’s government.

Thursday’s auction of the painting is expected to sell for as much as $1.5 million.