World War I

World War I, global conflict waged from 1914 to 1918 that caused more destruction and involved more participants than any other conflict up to that time. The war's spread was facilitated by an interlocking system of military alliances that Europe had forged during the previous decades, ostensibly to keep the peace. These alliances comprised the Central Powers (primarily Germany and Austria-Hungary) and the Allies (primarily Russia, France, and Great Britain). Later, other nations joined one or the other of the blocks.

Causes of the war

The underlying causes of the conflict involved the rise of nationalism in Europe, the military buildup pursued by parties of both alliances, and the competition among various European countries for colonies. The immediate cause of the war was the assassination of Austrian Crown Prince Francis Ferdinand at Sarajevo on June 28, 1914, by a Serbian nationalist. Austria, looking for a pretext to suppress Slavic nationalist aspirations in the Austro-Hungarian Empire, declared war on Serbia (July 28), with the approval of Germany. Russia announced full mobilization (July 30), and France rejected a German demand that she declare herself neutral.

The two fronts

Germany declared war on Russia (Aug. 1) and on France (Aug. 3) and invaded neutral Belgium, the shortest route to Paris, in search of a quick victory in the west before Russia had time to muster all its forces in the east. The invasion prompted Britain to enter the war (Aug. 4) in support of Belgium and France. All the major members of the alliances were now committed to war.

The western front

German armies gained initial successes, sweeping through Belgium and into France. They were halted at the Marne River (First Battle of the Marne, Sept. 6–9, 1914) by French forces led by Gen. Joseph Joffre. This battle ended German hopes of quickly overrunning its opponents in the west, and by late Nov. 1914 war on the western front settled into a dreadful stalemate. For the next 3½ years, terrible trench warfare raged along a 450-mile (724-km)-long front extending across Belgium and northeastern France to the Swiss border.

The eastern front

In late Aug. 1914 the Russians invaded East Prussia, but were defeated by the Germans in the battles of Tannenberg and the Masurian Lakes, suffering about 250,000 Russian casualties. Austria-Hungary was less successful, failing to capture Serbia and losing its province of Galicia to the Russians. In Oct. 1914 Turkey joined the Central Powers against Russia. In a vain attempt to aid the Russians, the Allies in early 1915 sent a fleet to the Dardanelles and ground forces to the Gallipoli Peninsula. The thrust proved unsuccessful, and troops were evacuated in Dec. 1915 with losses of about 250,000.

Outside Europe

After the Gallipoli disaster, the Allies attacked Turkey through her empire in the Middle East, and were largely successful, leaving her in possession of little more than Anatolia. Farther afield, British, French, and South African troops overran Germany's African possessions, while the Japanese (who had entered the war in Sept. 1914) and Australasian troops captured German possessions in the Far East and the Pacific.

Attrition in the West

In 1915 Italy joined the Allies and engaged the Austrian army in the Alps. In 1916 German forces were repulsed in their attempt to take the French city of Verdun with fearful losses on both sides (about 315,000 casualties for the French and 280,000 for the Germans). Paul von Hindenburg and Erich Ludendorff, the heroic leaders of German forces in the east, took command in the west, Hindenburg as chief of general staff with Ludendorff his aide.

An Allied offensive late in the year (the Battle of the Somme), led principally by the British, was also unsuccessful, and by its end it had cost the Germans over 600,000 casualties, the British over 400,000, and the French nearly 200,000. Britain maintained a naval blockade of the continent while German submarines harassed Allied mercantile shipping. An attempt by the German fleet to lift the blockade at Jutland (May 1916) failed.

The final stages

In Mar. 1917 the Russian people, sick of the war that had cost them dearly, revolted and overthrew Tsar Nicholas II. In Apr. 1917 V.I. Lenin returned to Russia from his exile in Switzerland, and 7 months later, as head of the revolutionary Bolshevik government, sued for peace with Germany. The Germans dictated a harsh peace between the 2 nations in Mar. 1918 at Brest-Litovsk. The sinking of 3 U.S. merchant ships in Mar. 1917 together with the discovery of a German plan to try to persuade Mexico to go to war against the United States (the “Zimmermann Telegram”) caused the United States to declare war on the Central Powers in Apr. 1917. The American Expeditionary Forces, led by Gen. John J. Pershing, began arriving in France in mid-1917. Despite a massive final German offensive in 1918 that drove the Allies back to the Marne, Allied forces, boosted by U.S. contingents, eventually began to tell. In September the Hindenburg Line was breached. The Central Powers sued for peace, and an armistice went into effect on Nov. 11, 1918. The Treaty of Versailles (June 28, 1919), imposed on Germany, formalized the Allied victory. The dead on both sides totaled about 10 million.

Aftermath of the war

Europe had spent much of its economic resources on the war and was exhausted and in debt. The dissolution of old empires in Europe and Turkey spawned a host of new countries and allegiances, and the United States, unscathed in the war, emerged as the economic world power. An era of European dominance was clearly coming to an end, and a new, but very unsettled, world order was in the making.