The history of the present-day multi-branch National Museum in Poznan began in 1857, when the Museum of Polish and Slavic Antiquities was established in the Grand Duchy of Poznan by the Poznan Society for the Friends of Sciences.
In the 1870s the collections were extended by Seweryn Mielzynski's legacy. When gathering his collection, in 1870 Mielzynski had bought the Edward Rastawiecki collection and the following year donated the Miloslaw collection. A new seat of the Society and at the same time the first museum in Poznan was erected on the plot purchased by S. Mielzynski, opened in 1882, and used for the display of the objects gathered. In 1881 the Poznan Society for the Friends of Sciences named it the Mielzynski Museum.
In 1894 the Prussian authorities set up the first German museum, the Provinzial Museum in Posen (Poznan Provincial Museum), which since 1902 bore the name of Emperor Friedrich III (Kaiser Friedrich Museum). In 1904 representative premises of the Museum were opened in a modern museum building. An imposing eclectic edifice erected specifically to house the museum collection was designed by the renowned architect Karl Hinckeldeyn. Until today this building, currently housing the Gallery of Painting and Sculpture, remains one of the more interesting instances of monument exhibition architecture, with a centrally-situated lounge surrounded by display halls.
After Poland's regaining independence, in 1919 the museum was renamed into Muzeum Wielkopolskie (Museum of Wielkopolska) - the first public museum in sovereign Poland. In the period between the word wars, as a result of the merger of the German collection and that of the Mielzynski Museum and due to an intensive policy of purchases, a pioneering exhibition of painting and sculpture was established, one of the richest in the II Republic. At the same time two independent branches were set up: the Archaeological Museum, hosted by the building of the Poznan Society for the Friends of Sciences, and the Natural Museum at the Zoological Garden.
During World War II the German authorities re-established the Kaiser Friedrich Museum Posen. Due to the war and the activity of the German occupant numerous invaluable museum exhibits, for instance the natural and ethnographic collections, were irretrievable lost.
After the regaining of independence, the rebuilding of the Museum of Wielkopolska began as early as 1945 thanks to the efforts of Poznan art historians. In 1950 the Museum of Wielkopolska in Poznan was promoted to the rank of the National Museum.
In subsequent years the Museum acquired new branches, which were established in the following succession: in 1949 - the Museum in Rogalin, in 1949 - the Department of Folk Culture and Art (currently the Ethnographic Museum), in 1952 - the Museum of Musical Instruments, in 1954 - the Museum of the History of the City of Poznan, in 1962 - the Museum in Goluchow, in 1963 - the Military Museum of Wielkopolska, in 1965 - the Museum of Arts and Crafts (now Museum of Applied Arts), and the Adam Mickiewicz Museum in Smielów.
In addition, in 1975 the Department of Poster and Design was established at the Gallery of Painting and Sculpture; in 1982 the Department was expanded to include design collections. In 1992 the Gallery of Contemporary Art was extended by the Department of Photography, Film and Video.
In 1990 The Raczynski Foundation was founded at the National Museum in Poznan, established in London by Edward Count Raczynski to commemorate his one hundredth birthday. The Foundation currently owns exquisite painting collections from the Rogalin Gallery and other elements of the pre-war estate of the Raczynski family in Rogalin.