The news of the murder of the Austrian Heir Apparent, and his wife, in the streets of Serajevo, the capital of the province of Bosnia, on June 28, 1914, came upon the world like a thunderbolt from a blue sky. Demonstrations of popular indignation and hostility to Serbia followed in Vienna and other Austrian cities. The government press in Austria and Germany at once adopted the theory that the murder was the result of a wide-spread conspiracy in that country, although the assassin declared that he alone was responsible for the deed. Three weeks of ominous silence followed. On July 23, Austria presented an ultimatum to Serbia which it was impossible for that country to accept and remain an independent state, and to which was attached a peremptory demand for its entire acceptance in forty-eight hours; Within the period named, Serbia, with Russian approval, announced her willingness to accede to all the Austrian demands except two, which she desired should be referred to the Hague Tribunal.
At noon, on July 28, Austria declared war by an open telegram, and on the following night, the Austrian batteries on the left bank of the Danube, and their gun boats in the river, began a bombardment of Belgrade, the Serbian capital. An invasion of that country followed at once.
Meanwhile, the British Foreign Secretary, Sir Edward Grey, made strenuous efforts to maintain peace. He proposed a European conference to meet in London. France and Italy accepted without delay. The German Government replied on July 27 that it would accept mediation “in principle,” reserving its right to assist Austria if attacked. On July 30, Russia ordered a general mobilization of its army. At midnight of July 31 the German Ambassador at St. Petersburg (now Petrograd) presented an ultimatum from his government, requiring Russia to begin demobilization within twelve hours, or before noon on the following day. As soon as the limit named in the ultimatum had expired, both the German and Austrian Governments ordered a general mobilization of their armies and navies, and at seven o'clock that evening Russia was informed that a state of war existed between Germany and that country. On the same day, the President of the French Republic signed a decree for general mobilization, after receiving information that Germany had presented an ultimatum to Russia, and was beginning to mobilize, thus declaring the intention of France to stand by its ally. Sir Edward Grey had already instructed the British Ambassadors at Berlin and Paris to ask whether the neutrality of Belgium, in the event of war, would be respected by Germany and France. The French Government replied promptly in the affirmative, except in the event of some other power violating that neutrality, when France might find herself compelled in self-defence to act otherwise. On August 2 the German Government required Belgium to take up an attitude of friendly neutrality by permitting German troops to pass through her territory for the invasion of France, granting a time limit of twelve hours in which to make a reply. On the night of August 1 German troops invaded Luxemburg and during the following day, overran the entire Duchy and entered French territory near Longwy. On August 3 France informed Germany that a state of war existed between them in consequence of this invasion. Next day the British Government sent an ultimatum to Germany requiring that country to respect the neutrality of Belgium, which the German chancellor had already declared it would be necessary to violate. Before this was received, the German troops had entered Belgian territory in force and attempted next day, to capture Lieige, its chief industrial city, by direct assault. Having undervalued the efficiency of the garrison, they attacked in close formation and were repelled with heavy loss. On August 5, in consequence, the British Government declared the existence of a state of war between Great Britain and Germany, as having begun at eleven p.m. on the preceding day. It is worthy of remark that all belligerents sedulously abstained from making a distinct declaration of war. Italy announced its intention of remaining neutral on the ground that the war undertaken by Austria was an aggressive conflict.
For many years the governing classes in Germany had been schooled in the belief that this gigantic struggle between the great powers of Europe was inevitable and must result in “world power or downfall” for Germany. They had diligently prepared for it by taking every measure which the resources of the country would permit to increase its military and naval strength. The deepening of the Kiel canal had been accomplished. This gave the navy a safe harbour of refuge with outlets at once into the Baltic and the North sea. It has been aptly compared to a “fox's earth with a double entrance.” The law for the immense increase of the army had not yet come into full effect, and the projected preparations for offensive warfare were not entirely completed. Every conceivable plan for the invasion of France as the most redoubtable adversary had been critically considered. There were three possible routes for this invasion: one leading directly from Germany into France was barred by a chain of great defensive fortresses, with the exception of the somewhat narrow gap of Mirécourt between Toul and Épinal. The other two passed through the neutral states of Luxemburg and Belgium. All of these were eventually to be utilized. The invasion was to take the form of a great tidal wave sweeping irresistibly across the frontier on the broadest front, and ultimately enveloping and destroying the French field army and dictating terms in the capital. Success must be gained by the utmost swiftness and ruthless energy in execution, combined with a decided numerical superiority. Owing to the great extent of the country, the incompleteness of its railway system and presumed inefficiency of its government, it was considered improbable that the mobilization of the Russian army could be effected in less than six weeks. In France, the mobilization period was two days longer than in Germany; consequently it seemed possible that the German army might overwhelm France and be in a position to turn effectively upon the Russians afterwards.
The course that would be pursued by Great Britain was a matter of vital importance to both countries. The German chancellor frankly thought it incredible that Great Britain would risk the existence of her empire for the sake of a mere “scrap of paper” as he scornfully described the treaty for the maintenance of Belgian neutrality. If Great Britain remained neutral, the superiority of the German and Austrian fleets was so great as to insure them naval supremacy. The French feared that British assistance, if given at all, would come so late as to be of small avail. The declaration of August 5 was made so promptly as to relieve them from their worst apprehensions in that respect.