 He later bought most of the Mannheimer Collection in 1944, including Rembrandt's "Jewish Doctor" – assisted by the threat of confiscation from the Nazi government of Arthur Seyss-Inquart – with the remainder of the collection being purchased in the same manner in France later on.The collecting of the "Sonderauftrag Linz" includes many such cases of forced sale, using funds from sales of Hitler's book "Mein Kampf" and stamps showing his portrait.Members of the "Sonderauftrag Linz" made a considerable number of purchasing trips throughout Europe, acquiring a significant number of artworks, and also arranged purchases through art dealers.