The assassination of francis Ferdiand and his wife Sophia. Who were visiting Sarajevo the capital of Bosnia on june 28 1914. The were assassinated by Serbian Granvillo princip a member of a secret society called the Black Hand. An ultimatum was issued by Russia the managers demanding that all secret societies should be suppressed. Secondly Serbia was to be dismissed all officials not liked by Austria.
Austrial policy were allow to carry out investigation in Serbia.
The Austrial accepted the first and rejected the second and the third.
Serbia accepted the first two demands and rejected the third.
The serbain requested that it should be carried to the international court of the league the Austrian refused and on july 28 1914 declared war on Serbia.
France was preparing to support Russia an German asked France to remain Neutral, when the French refused to remain neutral, the germans declared war on them on the third of August 1914
Britain reminded the Germans of Belgans neutrality established in London 1839 which the Kaiser described as a scrop of paper then declared war on Germany on the forth August 1914.