OutbreakPolitical
Assassination at Sarajevo
Archduke Franz Ferdinand of Austria-Hungary and his wife Sophie are shot dead in Sarajevo on 28 June by Gavrilo Princip, a Bosnian Serb nationalist.
Princip belonged to the Young Bosnia movement, supplied with weapons by the Serbian Black Hand secret society. The Habsburg court used the murder as a pretext to crush Serbian influence in the Balkans. After Berlin's 'blank cheque' of 5 July promising unconditional support, Vienna delivered an ultimatum designed to be rejected, then declared war on Serbia on 28 July — setting Europe's alliance system in motion.