From 1910 Robert von Mendelssohn had aggressively and presciently expanded the collection, selecting works by Pablo Picasso, Vincent van Gogh, Max Slevogt, Édouard Manet and Claude Monet.
[10] Reflecting the large social network of which the Mendelssohns were at the heart, members of Berlin's intellectual elite with whom he played chamber music in private included Albert Einstein.
Co-stars included Lotte Lenya, Peter Lorre, Fritz Kortner, Theo Lingen, Heinz Rühmann and Paul Hörbiger.
He drove a white Lancia cabriolet in which the seat covers were made of ermine,[2] and often appeared in public wearing a red leather suit[2] or a yellow silk dressing gown.
[3] In his parents' house in Grunewald he held high-profile social events at which leading figures from the arts and politics mingled with men from the gay community.
While Eleonora, who at this point was married to an Austrian, moved back to Castle Kammer [de], in Upper Austria, and not far from Salzburg.
[10] Francesco von Mendelssohn spent the summer of 1935 in Venice and then, travelling with Eleonora, Lotte Lenya, Kurt Weill and the impresario Meyer Weisgal, set sail in September from Cherbourg aboard the Majestic, in order to start a new life in New York City.
[17] The massive fortune that the von Mendelssohn siblings had inherited from their banker father was greatly diminished by the anti-semitic measures imposed by Nazis that accompanied in their emigration, but they remained wealthy by most standards and were able to provide financial support to other refugees.
However, fearing government reprisals if the switch was noticed, a cousin persuaded them to have the real pictures returned to Germany where Alfred Hentzen [de] arranged for them to be lodged with the central bank in order to prevent their sale abroad.
Francesco von Mendelssohn had a history of melancholy that predated his emigration, and in his American exile he became a high level depressive, also suffering badly from alcoholism after 1937.
The end of World War II and of Nazi Germany raised the possibility of restitution following the loss of the von Mendelssohn art collection.
Francesco was no longer in any state to attend to the matter, and it was left to his sister Eleonora to travel to Europe to try and recover the lost art works.
After Aldo Cima's suggestion that she should bribe the museum directors had been rejected, she sought to achieve restitution through a combination of appeals for reimbursement and attempts to buy some of the paintings back.
In the end her application for restitution was rejected by the German authorities in 1953, but by this time Eleonora von Mendelssohn was no longer in a position to know of it.
The portrait of Hendrickje Stoffels attributed to Rembrandt, which had been purchased for the "Fuhrer Museum" in Linz, was handed over by the US occupying forces to the Munich-based Treuhandverwaltung (public trusteeship administration).
After Mendelssohn's claim for restitution had been rejected it was loaned by the West German government to the Alte Pinakothek art gallery in Munich and then, in 1967, transferred to the Städel institute in Frankfurt.
Later, at a public hearing on the matter held before the district court in Vienna, no one turned up to represent the Mendelssohn family's position, and their application was again rejected.