The Jewish art historian and dealer Dr. Grete (Margarete) Ring (1887–1952) [FIG. 1, 2] was a niece of the painter Max Liebermann. One of the first female university students in Germany, Ring studied art history, archaeology and philosophy at the universities of Berlin and Munich before pursuing her graduate education. In Munich, the renowned art historian Heinrich Wölfflin (1864–1945) supervised her doctorate on Dutch 15th-and-16th-century paintings.

After embarking on her professional life at the Alte Pinakothek and the Neue Nationalgalerie, Ring joined the Kunstsalon Paul Cassirer in 1920 [FIG. 3, 4] on the recommendation of the art historian Max J. Friedländer (1867–1959). She edited and wrote scholarly texts for Cassirer’s auction catalogues and became a partner in the gallery in 1924.

By this time, and until 1933, Ring was living at Landgrafenstrasse 2, and at Landgrafenstrasse 4a from 1934 until 1938. She also frequented her summer bungalow in Sacrow near Potsdam, which was built in 1928–29 by her close friend, the architect Wilhelm Büning (1881-1958) [FIG. 5, 6].  

On 7 January 1926, Paul Cassirer took his own life when his wife Tilla Durieux filed for divorce. Following this tragedy, Ring took over the management of the Kunstsalon Paul Cassirer as co-owner with Dr. Walter Feilchenfeldt (1894-1953), who had been Cassirer’s partner since 1924. Ring was both an art dealer and scholar, editing Cassirer catalogues for the collections of Oscar Huldschinsky (1928) [FIG. 7, 8] and Dr. Albert Figdor from Vienna (1930), among others.  

She also wrote articles for the art periodical Kunst und Künstler, edited by Paul’s cousin Bruno Cassirer and built a significant collection of 19th-century drawings including works by Edgar Degas [FIG. 9].  

Ring became widely known through the discovery of the Otto Wacker (1898–1970) forgeries of Vincent van Gogh and her articles about the ensuing 1932 trial. While organising a Van Gogh exhibition in 1928, Ring and Feilchenfeldt found that  the art dealer Wacker’s contributions included forgeries. Later research revealed that he  had forged more than 30 works by the artist [FIGS. 10-13]. In 1932, Wacker was found guilty and sentenced to 19 months in prison and a fine of 30,000 Reichsmark.