The painting "Woman in Blue in Front of a Fireplace," circa 1937 by Henry Matisse. (AP Photo/Oystein Thorvaldsen, Henie-Onstad Art Centre)

Norway’s Henie Onstad Art Center will be returning the centerpiece of its collection, Henry Matisse’s 1937 painting “Woman in Blue in Front of a Fireplace,” after an investigation confirmed it had been stolen from a Jewish art dealer by Nazi leader Hermann Goering. The AP and Times of Israel report that the painting, now believed to be worth $20 million, belonged to Jewish art dealer Paul Rosenberg, and was looted from his home after he fled France for the United States in 1940.

Norwegian shipping magnate Niels Onstad acquired the painting in 1950 from a French art gallery and was reportedly unaware of its origins (Goering had sold it to a Parisian art dealer who was later convicted of dealing Nazi-looted art). When Onstad founded his namesake museum in 1968, the Matisse was its crown jewel.

The museum investigated the painting’s past only after being notified by the Rosenberg family of their claim to it in June 2012. The museum said that in the wake of the investigation — which it believes is the first of its kind undertaken in Norway — it has called upon the country’s government to establish a committee to actually meet its obligations under the Washington Principles. Similar reviews have been launched in the U.S., Netherlands and Germany.

“Ultimately, it was the strength of the moral claim that persuaded the Henie Onstad Art Center to restitute this painting unconditionally to the Rosenberg heirs,’ said Chris Marinello of Art Recovery Group, a lawyer representing the family.

While many countries have become more inclined to return Nazi-looted art in recent years—France returned three stolen works of art to the Jewish owners’ heirs earlier this month, timed with the French release of The Monuments Men—the international legal battles over stolen World War II-era property remain a grim undertaking.

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