On the restitution by the Bayerische Staatsgemäldesammlungen in 2020 of the oil painting 'Fischerboote bei Frauenchiemsee' by Joseph Wopfner to the heirs of Alfred Isay (1885–1948). The painting was part of the extensive collection of Abraham Adelsberger (1863–1940) of Nuremberg who gave it to Alfred Isay, his son-in-law, as security for a loan in 1932/33. Isay lost ownership of the painting in 1935, and the painting went to Martin Bormann, head of the Nazi Chancellery in Berlin. It was found by the Allies at the end of the war and, its rightful ownership unknown, handed over to the custody of the state of Bavaria. In 1956 Bavaria assumed ownership. The painting remained in their state collection for the next 64 years.
Bayerische Staatsgemäldesammlungen (Hrsg.): Jahresbericht. München: Museum, S. 100-111.