In 2006, when the Milwaukee Art Museum organized the exhibition Biedermeier: The Invention of Simplicity, it established itself as a center of study for the Beidermeier style that was popular in Central and Northern Europe from about 1815 to 1835.
Building upon the Museum’s strength in German and Austrian art—partly due to the ethnic background of Milwaukee—the exhibition brought to the spotlight to Biedermeier art. This period of art and design history was not only little-known in the United States, but the exhibition also proposed a whole new interpretation of the style that changed scholarship in Europe as well. You can read more about Biedermeier here in this review from the New York Times.
Or better yet, read the exhibition catalogue, available for purchase on the Museum Store site.