Museum Frieder Burda is showing a large retrospective of German artist Sigmar Polke. Sigmar Polke (born 1941) is one of the most important artists of postwar Germany. The huge exhibition at the Frieder Burda Museum in Baden-Baden combines the three major Sigmar Polke collections of Frieder Burda, Josef Froehlich and Reiner Speck. With its 170 paintings, âPolke - a retrospective. The collections of Frieder Burda, Josef Froehlich, Reiner Speckâ is one of the most comprehensive retrospectives that has been organized for many years. Polke â a retrospective: the collections Frieder Burda, Josef Froehlich, Reiner Speckâ. Museum Frieder Burda, February 3, 2007 to May 13, 2007. Impressions from the opening, February 2, 2006.