The assassination of Archduke Franz Ferdinand of Austria in June 1914 sparked the beginning of World War I. His murder in Sarajevo by Gavrilo Princip, a Bosnian Serb nationalist, triggered a complex web of alliances and tensions among European powers. Austria-Hungary's declaration of war against Serbia set off a chain reaction, activating alliances between major nations such as Germany, Russia, France, and Britain. This assassination is often cited as the immediate catalyst for a conflict that escalated into a global war, fundamentally altering the course of the 20th century and leading to significant geopolitical changes.