World War I (1914-18), also known as the Great War, was a military conflict mainly in Europe, among most of the world’s greatest powers. The Allies consisted of France, Britain, Russia, and America who fought against the Central powers of Germany, Austria-Hungary, and Turkey. The main causes of the Great War were imperialist, territory, and economic rivalries of the two sides. The German Empire was determined to establish itself as the preeminent power of Europe.
The Germans were also intent on challenging the naval superiority of Britain. The rampant nationalism especially evident in the Austro-Hungarian empire that ignited the immediate cause of hostilities. Archduke Francis Ferninand on June 28, 1914, the heir to the Austro-Hungarian throne, was assassinated at Sarajevo by a Serbian nationalist. The following month, after its humiliating demands were turned down, Austria-Hungary declared war on Serbia.
Other declaration of war followed quickly as every major power in Europe was in the war. On the Western Front, the Germans rampaged through Belgium, and proceeded onto Paris before advancing to the English Channel. After the battles of Marne and Ypres, the Germans became stalled. Grueling trench warfare and the use of chemical warfare began all along the front, and for the next three years the battle lines remained virtually stationary despite huge casualties at Verdun and it the Somme offensive during 1916.
On the Eastern Front, the Central Powers were successful. The Germans defeated the Russians (Aug. -Sept. 1914) at Tannenberg and the Masurian Lakes. Serbian and Montenegro fell by the end of 1915. In the south, the Italian campaigns were inconclusive, through they benefited the Allied cause by keeping large numbers of Austrian troops tied down there. In Turkey, the Allies’ ambitious Gallipolli Campaign (1915), an attempt to force Turkey out of the war, was a costly failure.
In the Middle East, T. E. Lawrence stirred Arab revolt against Turkey. America neutrality had been threatened since 1915, when the British ship Lusitania was sunk. By 1917 unrestricted German submarine warfare had caused the U. S. to enter the war on the side of the Allies. An American Expeditionary Force, commanded by General Pershing, landed in France and saw its first action at Chateau-Thierry (June 1917). In Marne (1918), the new Soviet government signed the Treaty of Brest-Litovsk with the Central Powers.
The Germans were stopped just short of Paris in the second battle of the Marne, and an allied counteroffensive was successful. The Turkish and Austro-Hungarian empires, disintegrating from within, surrendered to the Allies, as did Bulgaria. After revolution erupted in Germany, the armistice was signed on Nov. 11, 1918. The Treaty of Versailles and the other treaties that ended the war changed the face of Europe and the Middle East. Four great empires (Germany, Austria-Hungary, Russia, and Turkey) had disappeared by the end of the war.
Replacing them were governments ranging from monarchies and sheikdoms through constitutional republics to the Marxist socialist state of the USSR. The war itself had been one of the bloodiest in history, without a single decisive battle. A total of 65 million men women served in the armies and navies: estimated 10 million persons had been killed and double that number wounded. Such statistics contributed to a general revulsion against war, leading many to put their trust in multinational disarmament pacts and in the newly formed League of Nations.