Europe 1914: Outbreak of the Great War
On July 28, Austria-Hungary attacked Serbia, starting the First World War. Facing war with France and Russia, Germany attempted to quickly defeat France first by moving through neutral Belgium. However, the violation of Belgium's neutrality prompted Britain to join the war on the side of the French.
23 Jul 1914 July Ultimatum▲
Austria-Hungary delivered an ultimatum to Serbia, demanding that the Serbians suppress all publications inciting hostility against Austria-Hungary, dissolve Serbian nationalist societies, purge Serbian military and civilian institutions of people deemed suspect by Austria-Hungary, and accept Austro-Hungarian police into Serbia to investigate Archduke Ferdinand's assassination and suppress subversive movements. The Serbian government was given until 5pm on 25 July to respond.
24 Jul 1914 Serbian reponse to July Ultimatum▲
The Serbian government accepted all points of the Austro-Hungarian ultimatum of 23 July, except for allowing Austro-Hungarian police to operate in Serbia. In response to Serbian appeals, Russia attempted to mediate but Austria-Hungary refused to compromise on the ultimatum or extend its 48-hour deadline.
28 Jul 1914 Outbreak of World War I▲
The Austro-Hungarian Empire declared war on the Kingdom of Serbia, in response to Serbia's rejection of Austria-Hungary's July Ultimatum. In the following days, Russia, Germany, France, and Britain all entered the conflict, resulting in the First World War.
28 Jul 1914 Russian mobilization▲
In response to the Austro-Hungarian declaration of war on Serbia, Emperor Nicholas II ordered the mobilization of the Russian Empire against Austria-Hungary. This partial mobilization - it excluded Germany in an attempt to limit the war - was protested by both Russian Foreign Minister Sazonov and the Russian War Minister General Vladimir Sukhomlinov, who believed that partial mobilization was technically impossible and considered Germany's attitude already belligerent. On 30 July the Emperor relented and ordered a general mobilization.
1 Aug 1914 German declaration of war on Russia▲
Alerted of Russian mobilization against Germany, Kaiser Wilhelm II ordered German mobilization and declared war on Russia. As per the Schlieffen Plan, Germany immediately prepared for the invasion of Luxembourg and Belgium on the assumption that France would enter the war. Although the British proposed that they would stay neutral if Germany did not attack France, the Kaiser was unable to get his generals to agree to this request as pausing the invasion was technically impossible.
1 Aug 1914 French mobilization▲
In response to German mobilization and the German declaration of war on Russia, the French government ordered general mobilization.
4 Aug 1914 British entry into World War I▲
In response to the German invasion of Belgium - whose neutrality was safeguarded by the 1839 Treaty of London - the United Kingdom declared war on Germany, bringing the British Empire into World War I.
4 Aug 1914 German invasion of Belgium▲
On 2 August 1914, Germany occupied Luxembourg and sent an ultimatum to Belgium, demanding passage through the country. When Belgium refused, Germany declared war on France on 3 August and on Belgium the following day. German troops immediately crossed the border, launching an offensive against the Belgian city of Liège.