In acquiring the Rheinen collection on February 4, 1909, the city of Mülheim an der Ruhr laid the foundation for a museum that has given rise to the Heimatmuseum (Museum of local history) at Tersteegenhaus and today’s Kunstmuseum. Initially, however, the City Collection was kept at Robert Rheinen’s home, located at Schollenstrasse 2. In 1912, it moved into the classical-style Vorstersche Villa and became the Städtisches Museum (City Museum).
Under the leadership of the art historian Werner Kruse, the museum moved again in 1922, this time to the Landratsamt (Court House) in Teinerstrasse. A bombing in June 1943 destroyed the museum and a large portion of its collection, inventories, files, and library. The remains were stored in the City Hall’s cellar then housed in temporary facilities during the post-war era.
In the 1960s, parts of the collection were presented at Schloss Styrum (Castle Styrum) and in the “art cabinet” at the city library. In 1970, the museum was at last able to move into its own space at Leineweberstrasse 1. With the move to the old post office building in 1994, the Kunstmuseum finally has a permanent home of its own after many itinerant years.