A Norwegian museum said it has agreed to return a Matisse once looted by Hermann Goering to the family of Jewish art dealer Paul Rosenberg.

The 1937 painting, “Woman in Blue in Front of a Fireplace,” has been the centerpiece of the Henie Onstad Art Center near Oslo since the museum was established in 1968 by shipping magnate Niels Onstad and his wife, Olympic figure-skating champion Sonja Henie.

The museum said in a statement Thursday that although it acquired the painting in good faith, it has “chosen to adhere to international conventions and return the painting to Rosenberg’s heirs.”

Norway is a signatory of the 1998 Washington Conference Principles on Nazi-Confiscated Art, which requires museums to review their collections for potentially looted works and when such a work is found, to try to locate rightful owners.

Now worth an estimated $20 million, the painting was taken by Goering after Rosenberg fled to New York in 1940, and sold to a Parisian art dealer later convicted of dealing in Nazi looted art. It was acquired from a different French gallery in 1950 by Onstad, who was apparently unaware of its provenance.

Hitler and Goering inspecting confiscated works of art. (photo credit: courtesy Yad Vashem)

Hitler and Goering inspecting confiscated works of art (photo credit: courtesy Yad Vashem)

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.

The museum’s decision was announced on the same day that a German panel ruled against the heirs of four Jewish art dealers in a complicated case of a monumental collection of medieval religious art known as the Welfenschatz, or Geulph Treasure.

Valued at some 200 million euros, the Christian jewel-encrusted, gold devotional icons, altars and reliquaries, 44 in all, are currently housed within Berlin’s Prussian Cultural Heritage Foundation (SPK) museum system. After Thursday’s verdict from the mid-January hearing by the Advisory Commission in connection with the return of Nazi-confiscated art, especially Jewish property, the SPK will apparently retain possession.

The heirs maintained that their ancestors had no choice but to sell the Christian artifacts in 1935 to the Nazi government for less than their value.