World War I

July Crisis and Declarations of War

After the assassination of the Archduke Franz Ferdinand, Austria-Hungary waited for three weeks before deciding on a course of action. The army was on leave to help gather the harvest, which practically denied Austria the possibility of military action at the time. On July 23, assured by unconditional support of the Germans should war break out, it sent an ultimatum to Serbia containing many demands, among them that Austrian agents would be allowed to take part in the investigation, and in general holding Serbia responsible for the assassination. The Serbian government accepted all the terms, except that of the participation of the Austrian agents in the inquiry, which it saw as a violation of its sovereignty. Emboldened by last minute Russian support, Serbia rejected the ultimatum. Austria-Hungary, in turn, rejected the Serbian reply on July 26. Breaking diplomatic relations, the Austro-Hungarian Empire declared war on Serbia on July 28 and proceeded to bombard Belgrade on July 29. On July 30, Austria-Hungary and Russia both ordered general mobilization of their armies.

The Germans, having pledged support to Austria-Hungary, sent Russia an ultimatum on July 31 to stop mobilization within 12 hours. The same day, Raoul Villain assassinated French socialist leader Jean Jaurès, a leading anti-war campaigner. On August 1, with the ultimatum expired, the German ambassador to Russia formally declared war. On August 2, Germany occupied Luxembourg, as a preliminary step to the invasion of Belgium and the Schlieffen Plan (Germany had planned to attack France first according to the plan, and then Russia, which had already gone wrong). The same day, yet another ultimatum was delivered to Belgium, requesting free passage for the German army on the way to France. The Belgians refused.

At the very last moment, the Kaiser Wilhelm II asked Helmuth von Moltke the Younger, the German Chief of General Staff, to cancel the invasion of France in the hope this would keep Britain out of the war. Moltke, horrified by the prospect of the utter ruin of the Schlieffen Plan, refused on the grounds that it would be impossible to change the rail schedule - "once settled, it cannot be altered". (Tuchman, 1994)

On August 3, Germany declared war on France and invaded Belgium on August 4. This act – violating Belgian neutrality to which Germany, France, and Britain were all committed to guarantee – gave Britain, which up to that point had yet to choose a side in the conflict, a reason to declare war on Germany on August 4.