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
Assassination of Archduke Franz Ferdinand advocate of increased federalism and widely believed to favor trialism, under which Austria-Hungary would be reorganized by combining the Slavic lands within the Austro-Hungarian empire into a third crown. A Slavic kingdom could have been a bulwark against Serb irredentism, and Franz Ferdinand was therefore perceived as a threat by those same irredentists. Princip later stated to the court that preventing Franz Ferdinand's planned reforms was one of his motivations. The day of the assassination, June 28 (June 15 in the Julian calendar), is the feast of St. Vitus. In Serbia, it is called Vidovdan and commemorates the 1389 Battle