World War I: Key Events and Turning Points
The Outbreak of War
On June 28, 1914, Franz Ferdinand, heir of the Austro-Hungarian Empire, was assassinated in Sarajevo, the capital of Bosnia, which had been occupied by Austria-Hungary since 1908. The assassin was a Bosnian student with links to Serbian nationalist organizations. Austria-Hungary, encouraged by Germany, accused Serbia of the murder and declared war on July 28. Russia declared war on Austria-Hungary to protect Serbia, and Germany declared war on Russia and France. Britain declared war on Germany and Austria-Hungary after the German army invaded Belgium. Only Italy remained neutral. The confrontation between Austria-Hungary and Serbia had become a European war.
The War of Movement
The war began on the Western Front when the German army suddenly attacked France through Belgium and Luxembourg (the Schlieffen Plan). The Germans hoped to win quickly in order to concentrate on the Eastern Front. At the beginning of September 1914, the Germans were 40 km from Paris. However, the French and British armies halted the advance in the Battle of the Marne. On the Eastern Front, Germany defeated Russia in the Battle of Tannenberg, but the Russians recovered and reached the border of the Austro-Hungarian empire. In the Balkans, Serbia halted Austria-Hungary’s advance.
Trench Warfare
After the Battle of the Marne, the Western Front remained static. Trenches were built from Switzerland to the North Sea. Even the smallest advances made during this phase resulted in huge casualties. From that moment, both the Central Powers (allies based on the Triple Alliance agreement) and the Allied Powers (allies based on the Triple Entente agreement) had to find new allies that could provide more soldiers. The Ottoman Empire entered the war at the end of 1914, followed by Italy and Bulgaria in 1915, and Romania in 1916. The Germans launched a new offensive on the Western Front in 1916 but were stopped by the French in the Battle of Verdun. The French and British attacked the German lines in the Battle of the Somme. Both offensives achieved very little despite the huge casualties on both sides.
1917: The Final Phases of the War
1917 was a decisive year for the war. On the one hand, the terrible conditions of trench warfare caused many soldiers to desert, and there were many revolts at the front. On the other hand, Russia signed the Treaty of Brest-Litovsk with Germany (1918) after the Bolshevik Revolution and withdrew from the war. The United States joined the war in 1917 for several reasons, primarily as a result of the sinking of the American ocean liner, Lusitania, in 1915 by Germany. Although war was already being waged in the colonies of European empires, the intervention of the United States made it a true global conflict. In 1918, the Allies defeated Austria-Hungary on the Eastern Front, and the Austro-Hungarian and Ottoman empires surrendered and called for an armistice. The Germans were defeated on the Western Front in the Second Battle of the Marne. There were revolts in the German army and navy, as well as demonstrations of workers against the government. As a result, the Kaiser abdicated, and Germany surrendered. An armistice was signed on November 11, 1918, ending the war.