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<< The Austrian ultimatum for Serbia​ | Phases of the European diplomatic crisis in summer 1914 |​ ​The first year of war (1914)​ >>

​​​​​On 23rd July, after having made sure of the unconditional support by the German allied, Austria issued a 48-hour ultimatum to Serbia: the request to suppress the subversive movements against Austria-Hungary through the involvement of the Austrian Forces and the use of punishments for guilty people.
On 25th July, Serbia reacted by rejecting the detrimental pretensions of its national supremacy and ordered a partial mobilisation.
On 25th July, Austria-Hungary declared the Serbian response unsatisfactory; there were the interruption of the diplomatic relations and a partial mobilisation of Austria.
Between 20th and 23rd July, the French President Poincaré and the Prime Minister Viviani visited Russia; France reaffirmed its will to fulfil​​ the treaty obligations; on 25th Russia decided to support Serbia in spite of the Britain and German attempts to mediate (Conference of the Ambassadors, direct negotiations between Russia and Austria-Hungary).
On 28th July, Austria-Hungary declared war to Serbia. On 30​th​ July there was a general mobilisation by Russia. The Chief of the German General Staff Von Moltke increased the pressure on the Chief of the Austrian General Staff so that he ordered the general mobilisation and refused the mediation attempts by the German Chancellor Bethmann-Hollweg who feared for the British involvement in the war: in Germany there was no alliance between the military Chiefs and the political ones. As consequence, there was a general mobilisation by Austria-Hungary.
Germany proclaimed the “danger of an imminent war” and issued an ultimatum to Russia for suspending the mobilisation and in a second ultimatum asked France (18 hours) to declare its neutrality in case of a German-Russian conflict.
In order to guarantee its neutrality France had to give Germany the Toul and Verdun fortresses.
Russia did not reply to the ultimatum and as consequence the German Army mobilisation started on 1st August, followed by the declaration of war against Russia.
France declared that “it would have acted in accordance with its interests” and so on 8th August Germany declared war to France.
Belgium refused to give Germany the consent to cross its territory but on 3rd/4th August the German troops broke into the Belgium border.
On 1st August England reacted by mobilising its fleet and the following day it ensured France on the defence of the North Sea coast. On 3rd August an ultimatum was issued to Germany asking to respect the Belgium neutrality.
​​​England went to war against Germany. As consequence Serbia declared war to Germany (6th August), Austria-Hungary declared war to Russia (6th August), France declared war to Austria-Hungary (11th August) and England declared war to Austria-Hungary (12th​ August).