During his time in Paris in the 1870s Liebermann began collecting reproductions of works by his role model and mentor, Jean-François Millet, the most prominent painter of the Barbizon School. In 1876 he acquired his first original piece – a landscape by Theodore Rousseau, another member of this school. However, Liebermann did not start assembling his art collection in a systematic manner until after 1884, when he got married and settled in Berlin. From the 1890s onwards, he bought works by Edgar Degas, Edouard Manet, Claude Monet, Camille Pissarro and Auguste Renoir, and thus became a pioneering collector of Impressionist art.
Although Liebermann had initially had his reservations about Post-Impressionism, as a collector he proved to be very open to this artistic movement. In 1907 he bought one of Vincent van Gogh's Kornfeld [Wheat Field] paintings, and in 1909 and 1916 he acquired two paintings by Paul Cézanne, including his exuberant early work Die Fischer – Ein Tag im Juli [The Fishermen (Fantastic Scene)]. Along with works by representatives of the Barbizon School, his collection included German Realists and Impressionists such as Wilhelm Leibl, Fritz von Uhde or Max Slevogt. The fact that his collection also had a local emphasis is borne out by the presence of works by Berlin artists; these included Johann Gottfried Schadow, Carl Blechen, Franz Krüger, Adolph Menzel and Carl Steffeck, who had been his first teacher. Among the works by the old masters in his possession, the drawings and etchings by Rembrandt are particularly worthy of note. In later years Liebermann also extended his collection of graphic works. One example of this new focus is Honoré Daumier, whose work he began to appreciate as a collector around 1910; besides a painting and a number of drawings, Liebermann owned a large number of Daumier's lithographs.
During the Nazi era, large sections of Liebermann's collection were dispersed in different directions, but in 1933 he did manage to arrange for fourteen works to be stored at the Kunsthaus Zürich. Following the artist's death in 1935, Nazi measures to expropriate Jewish property and assets meant that Martha, his widow, was forced to sell a number of works. Some of the money raised by selling these works was intended to finance her planned emigration, which sadly never happened. Today, the artworks that once constituted Liebermann's collection are held in a number of museums and private collections in Europe and the United States; grouped works from the collection are no longer together. All of the works on show in this room once belonged to Liebermann's collection.