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
Russian entry into World War I of Austria of Germany and the Austro-Hungarian Empire. The consensus of scholars includes scant mention of Russia, and briefly mentions Russia's defense of Orthodox Serbia, its pan-Slavic roles, its treaty obligations with France, and its concern for protecting it status as a great power. The Archduke Franz Ferdinand of Austro-Hungary was assassinated by Bosnian Serbs on 28 June 1914 to protest Austrian takeover of a largely Slavic province. Vienna was unable to find evidence that Serbia had sponsored the assassination but a month later issued an ultimatum to Serbia, which it knew would be rejected and thus lead to war.