The war sparked by the assassination of Archduke Franz Ferdinand was World War I. The heir to the Austro-Hungarian throne was assassinated on June 28, 1914, in Sarajevo by Gavrilo Princip, a Bosnian Serb nationalist. This event set off a chain reaction of diplomatic crises and alliances that led to the declaration of war in July 1914. The complex web of alliances between major powers, including Austria-Hungary, Germany, Russia, France, and Britain, escalated the conflict into a full-scale war. This conflict lasted until 1918, resulting in significant loss of life, political changes, and the eventual reshaping of national borders in Europe.