Whilst stationed in Rome during the Second World War, Bismarck would pass on German intelligence to the Italian Foreign Office and privately speak ill of the Nazi regime, in particular Ribbentrop, Goering, and Hitler.

[1] "The Prince used to tell Italian Foreign Office officials much of what he knew, but, as Ciano discovered, 'he was hellishly afraid of being found out, and implored me in Heaven's name not to pass his confidential information to anyone.'

They had run from the unsystematic butchery of the Croatian fascists, the Ustaši, but by the middle of 1942 they were threatened with the systematic extermination planned for them under the Nazi "new order" in Europe.

By refusing the German request and disobeying an explicit order of the Duce, the conspirators set a perilous course which in the end crossed not merely the murderous ambition of Mussolini but that of Hitler, Himmler and the SS.

Bismarck had orders to demand that the Italian government instruct its military authorities "to actuate those measures devised by the Germans and the Croatians for a transfer in mass of the Jews of Croatia to territories in the East".

Bismarck himself had whispered the truth to the cabinet chief of Count Ciano: the Jews were not being transferred to the east to work but to die.

At the end of the war Bismarck's home of Friedrichsruh became one of the headquarters of the "White Buses" operation undertaken by the Swedish Red Cross and the Danish government in the spring of 1945 to rescue concentration camp inmates in areas under Nazi control and transport them to Sweden, a neutral country.

[7] In spite of its clearly visible Red Cross markings on the roof, the Friedrichsruh manor house was destroyed during a RAF raid in the last days of World War II, due to the (false) rumor that Heinrich Himmler was hiding there.

In the 1950s Bismarck considered becoming a member of the FDP (the liberal party), which offered him a nomination for Parliament, but eventually joined the Christian-conservative CDU instead.