The Guns of August Addressed is prewar military planning, as done by the major powers in Europe. Included are the German Schlieffen plan, France's offensive Plan XVII, joint British and French arrangements, and Russia's approach to a future European war. "Outbreak" starts with a short introduction, which briefly mentions the event that triggered World War I. On June 28, 1914, in Sarajevo, Gavrilo Princip, a Serbian nationalist, assassinated the heir apparent to the throne of Austria-Hungary, the Archduke Franz Ferdinand and his wife Sophie, Duchess of Hohenberg. European-wide diplomacy and military preparations during July are then referenced. Chapters 6 to 9 commence with August
Muhamed Mehmedbašić the way to Sarajevo, gendarmes searched the train; fearing they were on to him, he threw the knife out the window. Potiorek was planned to be assassinated at the end of March 1914, when the new mufti Čaušević was to be enthroned in Sarajevo. However, upon hearing that Archduke Franz Ferdinand of Austria would come to Sarajevo on Vidovdan, the Black Hand changed their minds. The Archduke's scheduled visit on Vidovdan (28 June), a Serbian national holiday, was perceived as an insult. Ilić summoned Mehmedbašić and informed him on 26 March that the plan now was to murder Archduke Franz