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
Sophie, Duchess of Hohenberg and Archduke Franz Ferdinand. Through her grandmother's family, the Berchtolds, she is distantly related to former Austro-Hungarian foreign minister Count Leopold Berchtold and to Austrian conductor Nikolaus Harnoncourt. Cardinal Christoph Schönborn is a great-grandson of her niece, Marie Chotek. Sophie, Duchess of Hohenberg Sophie, Duchess of Hohenberg (; ; 1 March 1868 – 28 June 1914), was the wife of Archduke Franz Ferdinand of Austria, the heir to the Austro-Hungarian throne. Their assassination in Sarajevo sparked a series of events that eventually led to World War I. Sophie was born in Stuttgart as the fourth daughter of Count Bohuslav Chotek