Could the event that triggered the 'war to end all wars' have been prevented? The shot that killed Archduke Franz Ferdinand and directly led to the outbreak of the First World War is known as the 'shot heard around the world'. Far less widely known is the fact that the Archduke owned, but on that fateful day did not wear, a bulletproof vest manufactured by Polish priest-turned-inventor Casimir Zeglen. Using a reconstructed bulletproof vest and a Royal Armouries Browning Model 1910 pistol identical to that used by the Archduke's assassin, Lisa Traynor highlights the risks associated with power and status in the early 20th century. Assessing the design and composition of Zeglen's armours, she charts the technological development of pistols used during this period's assassination plots. Testing her findings on a replica of the Archduke's bulletproof vest, Traynor poses the haunting question: had Franz Ferdinand been wearing body armour on the day of his assassination, would it have saved his life? Featured in the BBC TV series Sword, Musket and Machine Gun: Britain's Armed History, this fascinating book breaks new ground in our understanding of the outbreak of the First World War.