WARSAW, Poland (AP) – Peter Paul Rubens’ 17th-century masterpiece Portrait of a Lady will be offered to the highest bidder on March 17 at DESA Unicum auction house in Poland. The Flemish master’s oil-on-canvas portrait of a dark-haired woman in a rich black velvet dress has an estimated value of 18 million to 24 million zlotys ($4.5 million-$6 million).