 Complete the following phrase:  At the age of seventeen, he enrolled at the Kunstakademie Düsseldorf, where he studied landscape painting with Eugen Dücker. From 1884 to 1886, he was Dückers master student. In the latter year, he went to the United States, to join a group of German painters in Milwaukee who had been commissioned by the American Panorama Company to paint cycloramas and panoramas of the Civil War. A photograph from that period shows him and his fellow artists in front of a cyclorama of the 