The major event involving the assassination of Archduke Franz Ferdinand occurred on June 28, 1914, and is widely considered the trigger for World War I. Ferdinand, heir to the Austro-Hungarian throne, was assassinated in Sarajevo, Bosnia, by Gavrilo Princip, a member of a nationalist group seeking independence for Slavic peoples. This assassination led to a complex web of alliances and tensions in Europe escalating into a full-scale war. Following the event, Austria-Hungary issued an ultimatum to Serbia, which ultimately failed to satisfy the demands, leading to a declaration of war. This set off a chain reaction of conflicts involving multiple nations, transforming global geopolitics.