NEW YORK, NY.- The heirs of a woman who was forced to surrender a painting to the Nazis were dealt a blow Tuesday in a decades-long legal feud between them and the Spanish museum that now owns the work, when a California appellate court ruled that the museum should retain ownership.

The ruling, in one of the longest-running Nazi restitution cases, involves a Camille Pissarro painting titled “Rue Saint-Honoré Après-midi, Effet de Pluie” (“Rue Saint-Honoré in the Afternoon, Effect of Rain”) that is estimated to be worth millions of dollars. The painting was surrendered by a Jewish woman, Lilly Cassirer, to get an exit visa from Germany in 1939. The work was bought by the Thyssen-Bornemisza Collection Foundation, and eventually ended up in a museum owned by the Spanish government.

On Tuesday, a three-judge panel of the U.S. Court of Appeals for the 9th Circuit ruled that Spanish law, not California law, applies to the case, and that the museum has “prescriptive title” to the painting after buying it in 1993.

Sam Dubbin, a lawyer for David Cassirer, Lilly’s great-grandson and the principal plaintiff in the case, wrote in an email to The New York Times that the court’s decision was incorrect and that Cassirer would be seeking an en banc review by a panel of 11 judges.

“The Cassirers believe that, especially in light of the explosion of antisemitism in this country and around the world today, they must challenge Spain’s continuing insistence on harboring Nazi looted art,” Dubbin wrote. “This decision also gives a green light to looters around the world.”

Lawyers for the museum said in an email that the ruling was “a welcome conclusion to this case.”

Cassirer’s heirs, who now live in Southern California, have been locked in the legal battle against the museum since 2005, when Claude Cassirer, David’s father (who has since died), initially filed a lawsuit. The heirs contend that the museum should return the painting to the original owners. The museum’s lawyers have argued that its curators did not know the painting was stolen and under Spanish law bear no responsibility for returning it, while Cassirer’s lawyers have argued that the museum’s curators would have discovered the theft if they had done their due diligence in researching the history of the painting.

The key legal issue has been whether Spanish or U.S. law should govern in this situation. The Cassirer family faced a series of setbacks after multiple courts found that Spanish law governed the case, and the museum retained ownership of the painting.

The Cassirers then petitioned the Supreme Court, which took the case. In a unanimous decision in 2022, the court sent the case back to the appellate level, ruling that the lower court should compare Spanish law with California law, instead of federal law, in evaluating the case.

Neither party to the lawsuit disputes the facts of the case surrounding Lilly Cassirer’s surrender of the work. And in 1958, Germany paid her compensation of about $265,000 in today’s dollars.

The painting was later sold at a Nazi government auction and passed through the hands of a variety of collectors, including ones in the United States, before being purchased by Baron Hans Heinrich Thyssen-Bornemisza in 1976. The Spanish government bought the baron’s art collection, including the painting, in 1993 and it has been on display at the museum ever since. In 2000, Claude Cassirer discovered that the painting was at the museum.

In a concurring opinion for the 9th Circuit, Judge Consuelo M. Callahan wrote that while she agreed with the court’s decision that the Spanish museum was not legally obligated to return the painting, she believed the museum still had a moral duty to do so.

This article originally appeared in The New York Times.