Dec. 5 (UPI) -- The U.S. Supreme Court on Monday will hear arguments in a case about whether Jewish heirs to a collection of medieval artifacts known as the Guelph Treasure who say their grandparents were forced to sell to the Nazis will be able to continue to sue the German government in U.S. courts.
Arguments will be heard by telephone conference call.
Jed Leiber of Los Angeles, New Mexico resident Alan Philipp and Gerald Stiebel of London sued the German government in U.S. courts in 2015, seeking the return of the more than 40 items, some dating back to the 11th Century, valued at a combined $276 million.
The Prussian Cultural Heritage Foundation appealed a ruling in the U.S. District Court for the District of Columbia rejecting arguments by German government lawyers that they were immune from foreign legal action under the Foreign Sovereign Immunities Act.
The treasure, known as the Welfenschatz in German, is on display at the Museum of Decorative Arts in Berlin.
The collection was purchased by a group of four Jewish art dealers in Frankfurt, Germany, in 1929, with the intent to flip the collection for a profit. When the Great Depression hit, the group was forced to hold onto about half of the collection.
In 1935, Saemy Rosenberg in Amsterdam sold remnants of the collection to the state of Prussia, for less than one-third of their purchase price, the heirs claim. Prussia was at that point under Nazi control and ruled by Adolf Hitler's second-in-command, Hermann Goering.
The plaintiff's claim that Goering later presented the Guelph Treasure to Hitler as a gift has been disputed by researchers from the German government.
Lieber, Rosenberg's grandson, and his co-plaintiffs initially argued for the return of the items to the German government under the Return of Cultural Property Seized as a Result of Nazi Persecution. The German government researched the claims and said that the 1935 sale of the artifacts was made at a fair price and not under duress.
"Our view is that Germany is the proper jurisdiction for a case which involves a sale of a collection of medieval German art by German art dealers to a German state," Hermann Parzinger, president of the foundation told ABC News.
The Trump administration and a group of U.S. lawmakers urged the Supreme Court to drop the case in October.
This article has been updated to correct the number of articles contested in the lawsuit; the correct name of the Berlin museum where they are displayed; and the dispute over whether the artifacts were gifted to Adolph Hitler.