The full set of three stamps in the memory of Archduke Ferdinand & Princess Sophie. These rare stamps issued 1917 during the period of Austro-Hungarian Empire (Austria-Hungary-Bosnia).On 28th of June 1914 (written in the stamps) Serb terrorists group assassinated Archduke Ferdinand (see his portrait in the stamps along with his Hungarian wife princess Sophie) while visiting the army in Sarajevo. First World War started directly after that assassination.