Some experts believe this 17th-century work now up for sale was originally stolen by the Nazis, but no clues to its prewar owner have turned up in years of searching.
Provenance probe of Nazi era trove goes on display in Switzerland thelocal.ch - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from thelocal.ch Daily Mail and Mail on Sunday newspapers.
When a Bern museum inherited a spectacular collection of some 1,600 artworks, including by masters like Monet, Gauguin and Picasso, it spent seven months mulling whether to accept the offer.