Outbreak of War: 28th June to 14th August,1914
28th June: Archduke Franz Ferdinand and Duchess Sophie von Chotkova were killed by Gavrilo Princip. Several members of the Black Hand group in Sarajevo were arrested and interrogated by the Austrian authorities. Under extreme questioning some of the men claimed that three members from Serbia, Milan Ciganovic, Dragutin Dimitrijevic and Voja Tankosic, had organised the plot.
6th July: The German government announces its full support for Austro-Hungary if it decides to take reprisals against Serbia.
9th July: The Austro-Hungarian government send Friedrich von Wiesner to Sarajevo to investigate the claims that the Serbian government was involved in a plot to kill Archduke Franz Ferdinand.
13th July: Wiesner reports to the Austro-Hungarian government that members of the Serbian Army were involved in the assassination of Franz Ferdinand.
21st July: Conrad von Hotzendorf convinces Emperor Franz Josef that Austro-Hungary could punish Serbia without the other major countries taking action.
23rd July: The Austro-Hungarian government makes fifteen demands on the Serbian government. This includes the demand they arrest the leaders of the Black Hand group based in Serbia and send them to face trial in Vienna.
24th July: Nikola Pasic and the Serbian government appeal to Russia for help against the proposed attack by the Austro-Hungarian Army.
25th July: Nikola Pasic tells the Austro-Hungarian government that he is unable to accept their fifteen demands, as it "would be a violation of Serbia's Constitution and criminal in law".
26th July: Russia promises that it will help Serbia if it is attacked by Austro-Hungary.
28th July: Austro-Hungarian declares war on Serbia.
31st July: Russia mobilizes its armed forces in support of Serbia. This includes the sending of troops to its borders with Germany and Austro-Hungary.
1st August: Germany declares war on Russia.
2nd August: Italy declares that it does not intend to honour its Triple Alliance obligations and will remain neutral.
3rd August: Germany declares war on France. Belgian neutrality was guaranteed by Britain under a treaty signed in 1839. Sir Edward Grey, Britain's foreign secretary, warns Germany that Britain would go to war if Belgium was invaded.
4th August: The German Army marches into Belgium. Britain declares war on Germany.
5th August: Austro-Hungary declares war on Russia.
10th August: France declares war on Austro-Hungary.
12th August: Britain declares war on Austro-Hungary.
14th August: France invades Lorraine.