In 1940, at the start of another invasion by Germany, a decision was made in Belgium to send the altarpiece to the Vatican to keep it safe during World War II. The painting was "en route" to the Vatican, but still in France, when Italy declared war as an Axis power alongside Germany. The painting was stored in a museum in Pau for the duration of the war, with French, Belgian and German military representatives signing an agreement which required the consent of all three before the masterpiece could be moved. In 1942, Adolf Hitler ordered the painting to be seized and brought to Germany to be stored in the Schloss Neuschwanstein castle in Bavaria. The seizure, led by senior museum administrator Ernst Buchner and aided by officials in France, was ostensibly to protect the altarpiece from war. After Allied air raids made the castle too dangerous for the painting, it was stored in the Altaussee salt mines, which greatly damaged the paint and varnish. Belgian and French authorities protested the seizing of the painting, and the head of the German army's Art Protection Unit was dismissed after he disagreed with the seizure. Following the war, in 1945, the altarpiece was recovered by the Allied group Monuments, Fine Arts, and Archives program and returned to Belgium in a ceremony presided over by Belgian royalty at the Royal Palace of Brussels, where the 17 panels were displayed for the press. French officials were not invited as the Vichy government had allowed the Germans to remove the painting.