World War I was caused in part by the two opposing alliances developed by Bismarckian diplomacy after the Franco-Prussian War. In order to diplomatically isolate France, Bismarck formed the Three Emperor's League in 1872, an alliance between Germany, Russia and Austria-Hungary. When the French occupied Tunisia, Bismarck took advantage of Italian resentment towards France and created the Triple Alliance between Germany, Italy and Austria- Hungary in 1882. In exchange for Italy's agreement to stay neutral if war broke out between Austria-Hungary and Russia, Germany and Austria-Hungary would protect Italy from France. Russia and Austria-Hungary grew suspicious of each other over conflicts in the Balkans in 1887, but Bismarck repaired the damage to his alliances with a Reinsurance Treaty with Russia, allowing both powers to stay neutral if the other was at war.
However, after Kaiser William II fired Bismarck in 1890, the traditional dislike of Slavs kept Bismarck's successors from renewing the understanding with Russia. France took advantage of this opportunity to get an ally, and the Franco- Russian Entente was formed in 1891, which became a formal alliance in 1894. The Kruger telegram William II sent to congratulate the leader of the Boers for defeating the British in 1896, his instructions to the German soldiers to behave like Huns in China during the Boxer Rebellion, and particularly the large- scale navy he was building all contributed to British distrust of Germany.
As a result, Britain and France overlooked all major imperialistic conflict between them and formed the Entente Cordiale in 1904. Russia formed an Entente with Britain in 1907 after they had reached an understanding with Britain's ally Japan and William II had further alienated Russia by supporting Austrian ambitions in the Balkans. The Triple Entente, an informal coalition between Great Britain, France and Russia, now countered the Triple Alliance. International tension was greatly increased by the division of Europe into two armed camps.
The menace of the hostile division led to an arms race, another cause of World War I. Acknowledging that Germany was the leader in military organization and efficiency, the great powers of Europe copied the universal conscription, large reserves and detailed planning of the Prussian system. Technological and organizational developments led to the formation of general staffs with precise plans for mobilization and attack that often could not be reversed once they were begun. The German von Schlieffen Plan to attack France before Russia in the event of war with Russia was one such complicated plan that drew more countries into war than necessary.
Armies and navies were greatly expanded. The standing armies of France and Germany doubled in size between 1870 and 1914. Naval expansion was also extremely competitive, particularly between Germany and Great Britain. By 1889, the British had established the principle that in order to maintain naval superiority in the event of war they would have to have a navy two and a half times as large as the second-largest navy. This motivated the British to launch the Dreadnought, invented by Admiral Sir John Fisher, in 1906. The Russo-Japanese War of 1904-1905 had demonstrated how effective these battleships were. As Britain increased their output of battleships, Germany correspondingly stepped up their naval production, including the Dreadnought. Although efforts for worldwide disarmament were made at the Hague Conferences of 1899 and 1907, international rivalry caused the arms race to continue to feed on itself.
The friction of an armed and divided Europe escalated into several crises in Morocco and the Balkans, which nearly ended in war. In 1905, Germany announced its support of independence for Morocco, the African colony that Britain had given France in 1904. The British defended the French, and war was avoided by an international conference in Algeciras in 1906, which allowed France to make Morocco a French protectorate.
Another conflict was incited by the Austria-Hungarian annexation of the former Turkish province of Bosnia in 1908. The Greater Serbian movement had as an object the acquisition of Slavic Bosnia, so Serbia threatened war on Austria-Hungary. Russia had pledged their support to Serbia, so they began to mobilize, which caused Germany, allied with Austria-Hungary, to threaten war on Russia. The beginning of World War I was postponed when Russia backed down, but relations between Austria- Hungary and Serbia were greatly strained.
A second Moroccan crisis occurred in 1911 when Germany sent a warship to Agadir in protest of French supremacy in Morocco, claiming the French had violated the agreement at Algeciras. Britain again rose to France's defence and gave the Germans stern warnings. Germany agreed to allow France a free hand in Morocco in exchange for part of the French Congo. In the Balkan Wars of 1912-13, the Balkan States drove the Turks back to Constantinople and fought among themselves over territory. Tensions between Serbia and Austria-Hungary increased when Austria-Hungary forced Serbia to abandon some of its gains.
Europe had reached its breaking point when on June 28, 1914, Archduke Francis Ferdinand, heir to the Austria-Hungarian throne, was assassinated in Sarajevo, Bosnia, by a Serbian nationalist belonging to an organization known as the Black Hand (Narodna Obrana). Immediately following the assassination Germany pledged its full support (blank check) to Austria-Hungary, pressuring them to declare war on Serbia, while France strengthened its backing of Russia. Convinced that the Serbian government had conspired against them, Austria-Hungary issued Serbia an unacceptable ultimatum, to which Serbia consented almost entirely.
Unsatisfied, Austria-Hungary declared war on Serbia on July 28, 1914. On July 29, Russia ordered a partial mobilization only against Austria-Hungary in support of Serbia, which escalated into a general mobilization. The Germans threatened war on July 31 if the Russians did not demobilize. Upon being asked by Germany what it would do in the event of a Russo-German War, France responded that it would act in its own interests and mobilized. On August 1, Germany declared war on Russia, and two days later, on France. The German invasion of Belgium to attack France, which violated Belgium's official neutrality, prompted Britain to declare war on Germany. World War I had begun.
