On June 28, 1914, Archduke Francis Ferdinand of Austria-Hungary was assassinated. He was murdered at Sarajevo, the capital of the Austrian province of Bosnia. The assassin was Gavrilo Princip, a Serbian terrorist. Austria claimed that Serbian government officials also belonged to Princip's group. For many years Serbia and Austria-Hungary had been unfriendly because Serbian patriots wanted to unite all Serbs into a single state. Serbs living in Austria-Hungary would be included. Austria-Hungary was strongly opposed to this (see Austria-Hungary; Serbia; Yugoslavia).

War Declared

Austria-Hungary now decided to use the assassination as an excuse to settle its quarrel with Serbia. It was backed by Germany. On July 23 Austria presented a warlike ultimatum to Serbia, allowing only 48 hours for an answer. Serbia suggested that some of Austria's demands be referred to the other European powers. Austria refused. On July 28 it declared war on Serbia. All the nations in Europe had been expecting war. For many years rival groups of nations had been making treaties and alliances. Europe had been divided into two camps. Germany, Austria-Hungary, and Italy were members of the Triple Alliance, or Central Powers. Russia, France, and England formed the rival Triple Entente Powers. Later they were called the Allies. The Balkan States sided with Serbia and the Allies. Serbia's enemies were on the side of the Central Powers. These alliances were brought into action July 28 by Austria's declaration of war. Within a week all of Europe was at war.

Other Nations Involved

On July 29 Russia mobilized its troops near the Austrian border. This move was made, Russia said, to keep Serbia from being crushed. However, Russia had plans in Turkey which had been blocked by Austria and Germany. Russia wanted to control Constantinople and the straits from the Black Sea to the Aegean Sea. Germany now demanded that Russia stop all its war measures. Russia refused. On August 1 fighting began on the German-Russian frontier. Germany declared war on France on August 3. This followed France's failure to agree to remain neutral in the war between Russia and Germany. France and Germany had been enemies in many previous wars. They had also been divided by the question of Alsace-Lorraine (see Alsace-Lorraine).

England Declares War

England and Germany had been growing more and more unfriendly before 1914. Germany claimed that England was trying to keep it from becoming a world power. With the start of the war Germany made clear that it planned to invade France through Belgium. Britain had signed a treaty guaranteeing the independence and neutrality of Belgium. On August 4 Britain declared war on Germany to protect Belgian neutrality. The rest of the British Empire immediately prepared to send troops. Japan entered the war on the side of the Allies on August 23. Italy decided to remain neutral for the time being despite its membership in the Triple Alliance. Many Italians favored joining the Allies. This would help Italy to get territories in Austria-Hungary in which people of Italian nationality lived.

Size and Costs of the War

World War I grew into the greatest war the world had ever seen. The amount of money spent was enormous. The direct cost of the war was about 200 billion dollars. The United States alone spent as much money as it did on all the expenses of the government from 1791 to 1914. More than 65 million men were mobilized for the armies and navies. Over 8 million lost their lives, and more than 21 million were wounded. Civilian populations worked as never before to produce enormous quantities of guns, munitions, and other supplies. Civilians also suffered more than in any previous war. Because they played such an important part, this was called "total war."

THE WAR DURING 1914

All the major powers had war plans for quick victories but no plans for a long, drawn-out stalemate. The German Schlieffen Plan named after Count Alfred von Schlieffen, a noted military strategist was designed to avoid a long, costly war on two fronts. It called for the German left flank to hold the French army on the Rhine River. The right flank was to wheel through Belgium, northern France, and around Paris. After defeating France, the Germans then planned to concentrate their forces against Russia. The French had agreed to respect Belgian neutrality. Therefore they could not go through Belgium to attack Germany. Instead they intended to concentrate their troops on the center and right flanks. They then planned to strike a blow against the Rhine front. The Russians planned to drive a wedge between Austria-Hungary and Germany. They then intended to make a direct attack on Berlin. Although all these war plans failed, the German Schlieffen Plan came close to succeeding. The German army almost reached Paris but was thrown back by the French in the first battle of the Marne, a decisive battle of the war and one of the most important in history.

French Defense on the Marne

The French army of about 4 million was practically equal in size to the German army. Only a third of the men, however, were fully trained first-line troops. The French were not surprised that the Germans came through Belgium. What they did not expect was that the Germans would immediately use so many of their reserves as first-line troops. This gave the Germans more effective man power. French and British troops met the attacking Germans at the Belgian frontier in August. The French were driven back at Charleroi. The British were driven back at Mons. Both armies were forced by the Germans to retreat south. By the beginning of September a part of the German army was moving past Paris. Before the Germans were able to surround the city, however, the French attacked the exposed German flank. They also counterattacked along the entire front. The first battle of the Marne was fought September 6-10. The Germans, forced to retreat, moved north again.

Trench Warfare and Blockades

With the hope of a short war now lost, the fighting on the Western Front settled down to trench warfare. Victories on the battlefield were soon being measured in yards. The British naval blockade of Germany became important to the overall strategy of the war. Germany's submarines, in turn, came very close to cutting off Britain from its supplies (see Submarine).

Turkey Declares War

Turkey joined the Central Powers on October 29. This cut off Russia's easy sea communications with its allies. It also threatened England's communications with the Far East through the Suez Canal. To prevent the fall of the canal, the Allies were forced to keep large forces near the eastern end of the Mediterranean Sea throughout the war. The stalemate on the Western Front was offset for Germany by its success against Russia on the Eastern Front. The Germans under the two brilliant generals Paul von Hindenburg and Erich von Ludendorff overwhelmingly defeated the Russians at Tannenberg in August 1914.

THE WAR DURING 1915

Germany and Austria made great efforts to defeat Russia in 1915. Early in the year the Russians entered Hungary. The Germans counterattacked on May 2. In fighting centered around Brest-Litovsk the Germans broke through the center of the Russian front. Russian forces were driven back as far east as Pinsk. The Germans took 750,000 prisoners, but the Russians fought on. There was a deadlock on the Western Front during 1915. This was due partly to a shortage of artillery shells. In April the Germans used the poisonous gas chlorine against the French at Ypres (see Ypres). Soon both sides were using various types of gas and gas-filled shells with devastating effects (see Chemical and Biological Warfare).

Italy and Bulgaria Declare War

In April 1915 Italy signed the secret Treaty of London. The treaty offered Italy a large piece of Austrian territory. On May 23 Italy declared war against Austria-Hungary. It did not declare war against Germany until August 1916, more than a year later. On October 11 Bulgaria joined the Central Powers against the Allies. Bulgaria then joined with Germany and Austria to overrun Serbia and Montenegro. This cleared a path to Turkey, which had been holding out against Allied attacks but was now in need of support against the Allies.

The Gallipoli Campaign

In February and again in March British warships tried to force their way through the Dardanelles. Their plan was to get aid to Russia by way of the Black Sea. Both attempts were unsuccessful (see Dardanelles). On April 25 Sir Ian Hamilton landed a force of Anzacs (Australia-New Zealand Army Corps) on the narrow Gallipoli peninsula. A combined land-and-sea drive was then planned against Constantinople. The Gallipoli expedition was a costly failure. In January 1916 the troops were withdrawn. Many were sent to Egypt to protect the Suez Canal, which was threatened by Turkey. A part of these troops later formed a British and Arab force under Gen. Edmund Allenby that captured Jerusalem. Allenby headed the Palestine Expedition (see Palestine). Another successful leader in this region was Britain's T. E. Lawrence. Lawrence led the Arab revolt against the Turks. His forces also captured Damascus for the Allies (see Lawrence, T. E.).

Germany's Submarine Campaign

Germany's submarine fleet intensified its blockade of Britain during 1915. In February Germany announced that the waters around Great Britain, including the English Channel, were in the war zone. In addition, Germany clearly stated that merchant ships found in this zone would be destroyed. This included the ships of neutral nations. On May 7 a luxury passenger liner, the Lusitania, was torpedoed and sunk off Kinsale Head, Ireland. Among the 1,198 persons drowned there were 124 Americans. Germany continued to build more and better submarines. By April 1917, when the United States entered the war, more than 3 million tons of British shipping had been sunk. This was 16 percent of the 1914 British merchant fleet. By 1915 the British were already beginning to fear that continued shipping losses might force England out of the war.

THE WAR DURING 1916

The German surface fleet did not challenge Allied control of the oceans until the battle of Jutland on May 31, 1916. The British cruiser fleet met the German high-seas fleet off the Danish coast. The British, commanded by Adm. John R. Jellicoe, suffered heavy losses in ships and men. Nevertheless, Adm. Reinhard Scheer was forced to withdraw the German fleet. The British then won a costly but strategic victory. The battle of Jutland was the most important naval battle of the war. It made possible the continued blockade of Germany.

Battles of Verdun and the Somme

On the Western Front the Germans launched a great offensive against the French at Verdun in February. Before the attack the Germans shelled the French with the most powerful artillery bombardment ever used in war. For a short time the Germans swept everything before them. Then the French checked the advance. The battle of Verdun continued for many months, with little change (see Verdun). In July the British came to the aid of the French with an offensive in the Somme River area. The artillery bombardment before the attack lasted for a week. The British gradually moved forward. When winter ended the fighting, they had driven a wedge nine miles deep into the German line.

How the Tank Was Named

During the Somme offensive the British introduced an armored vehicle with caterpillar treads. The machine had been developed secretly. Different parts were made in different factories. Some parts, which looked like they could be used to make containers for liquids, were called tanks by the workers. Tank came to be used as a code name during the weapon's development and later became its permanent name.

Changes in Leaders

The winter of 1916-17 marked the end of the first phase of the war and the beginning of the final phase. There were many changes in leaders as the Allies looked forward to victory. Sir Douglas Haig had replaced Sir John French as the commander in chief of British forces in December 1915. David Lloyd George was made prime minister of England in 1916, succeeding Herbert Asquith. The French replaced Marshal Joseph Joffre with Gen. Robert Nivelle. Marshal Henri Petain took over command from Gen. Nivelle. Gen. Erich von Falkenhayn was replaced by Paul von Hindenburg as the German commander. (see England, "History"; France, "History"; Germany, "History").

War in the Air

Balloons and airplanes were first used mainly to carry observers. By 1915 photographs of enemy positions were being taken from airplanes. Anthony Fokker, improving on a French device, developed a machine gun for the Germans that was synchronized to fire through the whirling propeller of a flying plane. The French and British soon had their versions of this synchronized machine gun. Both the Allies and the Germans sent up fighter planes to shoot down enemy observation planes. Fighter pilots and planes fought for control of the air throughout the war. Allied and German fighter pilots became international heroes (see Airplane; Machine Gun).

Zeppelin Raids

Germany's Count Ferdinand von Zeppelin had seen the value of the balloon as an aerial observation post in the American Civil War. Back home in Germany after the Civil War he developed a navigable airship. It was a balloon of rigid construction (see Balloon and Airship). A Zeppelin was first used to bomb London in May 1915. During the war Zeppelins made a total of 51 raids. However, 77 of the big ships were destroyed in storms or by Allied attacks from fighter planes and antiaircraft fire. Their use as a war weapon was finally abandoned. Antiaircraft guns were developed by both sides for use against bombing raids. A popular song of the day was 'Archibald, Certainly Not!' British pilots, when they were fired at by the inaccurate German antiaircraft guns, often laughed and sang this song. When they returned to their airfields, they would be asked, "Archibald give you any trouble today?" They would answer, "Archibald? Certainly not!" Archibald was soon shortened to "Archie," and German antiaircraft fire was called "Archie" throughout the remainder of the war.

American Fliers in Combat

The Lafayette Escadrille first in action April 20, 1916. This was a French squadron made up of American volunteers. It remained attached to the French Flying Corps until February 1918, when it transferred to the American Air Service. In April 1918 the United States Air Service had three squadrons at the front. The number grew until there were 45 American squadrons. Most of them were equipped with French aircraft.

THE WAR DURING 1917

On March 11, 1917, a revolution broke out in Russia. Four days later the czar abdicated. The new republican government under Alexander Kerensky said it would continue the war. The Russian people, however, were sick of the war. The revolutionists had formed the Bolshevik party (it was renamed the Communist party in 1918). On November 9 the Bolsheviks overthrew the Kerensky government and asked Germany for an armistice. On March 3, 1918, the Bolshevik government signed a separate treaty of peace with the Germans at Brest-Litovsk. By the terms of this treaty the Russians lost Poland and nearly all the territory bordering the Baltic Sea. They also had to surrender a large area of land in the Caucasus Mountains to Turkey.

The United States Declares War

American public opinion had been slowly but steadily setting against Germany since 1914. In January 1917 Germany launched an unrestricted submarine campaign. All vessels, neutrals included, were to be sunk without warning if found in a zone off the Allied coasts. This was a violation of international law. Although President Woodrow Wilson's great desire was for peace, he felt the United States was forced to go to war. War was declared April 6, 1917 (see United States, "History"; Wilson, Woodrow).

British Fighting on the Western Front

British troops did most of the heavy fighting on the Western Front in 1917. There was a series of mutinies in the French armies. Commander in chief Petain kept his troops out of major actions to build up their morale. Late in the year they gained some ground at Verdun. British losses were heavy. In one battle alone, for the high terrain near Ypres, their casualties were almost a quarter of a million men. Losses like these, plus the fact that Germany would now have more man power with troops released from the Russian front, made the Allied chances for victory doubtful.

Italy's Caporetto Disaster

War weariness also brought disaster on the Italian front. In October 1917 the Austrians and Germans suddenly attacked the Italian forces at Caporetto. A terrible rout resulted, costing the Italians 265,000 prisoners. It was now clear that unless America could turn the tide, 1918 might bring victory to the Germans.

World War I Cont.