Hansemann was born in
Berlin to
Adolf von Hansemann, a notable Prussian industrialist and manager of the
Disconto-Gesellschaft, a large financial holding. Since early youth Hansemann was a member of various German
nationalist organizations. As an owner of a large estate of
Pempowo (Pępowo) in the
Province of Posen, he was interested in Polish affairs. Thanks to his father's connections, in 1894 he entered in contact with
Otto von Bismarck, who supported the creation of a new, all-German nationalist organization that would unite all Germans interested in strengthening the German spirit and property in Polish-inhabited areas. As one of its founders, in 1894 Hansemann was elected to the board of the newly established
German Eastern Marches Society, a post he held until his death. As one of the closest associates and supporters of
Heinrich von Tiedemann, von Hansemann was active in other branches of the organization, notably holding the post of the editor in chief of the
Die Ostmark monthly. ==References==