Austria-Hungary declares war on Serbia

On this day, 102 years ago, one month to the day after Archduke Franz Ferdinand of Austria and his wife were killed by a Serbian nationalist in Sarajevo, Austria-Hungary declares war on Serbia, effectively beginning the First World War.

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After securing the unconditional support of its powerful ally, Germany, Austria-Hungary presented Serbia with a rigid ultimatum on July 23, 1914, demanding, among other things, that all anti-Austrian propaganda within Serbia be suppressed, and that Austria-Hungary be allowed to conduct its own investigation into the archduke's killing.
Though Serbia effectively accepted all of Austria's demands except for one, the Austrian government broke diplomatic relations with the other country on July 25 and went ahead with military preparedness measures.

Meanwhile, alerted to the impending crisis, Russia - Serbia's own mighty supporter in the Balkans - began its own initial steps towards military mobilization against Austria.


That night, Austrian artillery divisions initiated a brief, ineffectual bombardment of Belgrade across the Danube River.

Russia's ally, France, ordered its own general mobilization that same day, and on August 3, France and Germany declared war on each other.


The German army's planned invasion of neutral Belgium, announced on August 4, prompted Britain to declare war on Germany.

Thus, in the summer of 1914, the major powers in the Western world—with the exception of the United States and Italy, both of which declared their neutrality, at least for the time being - flung themselves headlong into the First World War.