High School World History · Unit 1 · 1914–1918

World War I, 1914–1918

How two pistol shots in Sarajevo became a war of empires, trenches, and revolutions.

On a summer morning in 1914, a young man fired a pistol in Sarajevo, a city most Europeans could not have found on a map. Within six weeks, the great powers of Europe were at war. By 1922, four empires were gone.

I am Herodotus. Long ago I wrote my Histories so that "the causes may be remembered" for which peoples went to war with one another. People call me the Father of History, but my real job was asking questions. This unit asks three big ones: Why did the war start? Why did it last so long? And why did the peace not hold?

The War in Brief

World War I (people at the time called it the Great War) was fought from 1914 to 1918 between the Allies (France, Britain, Russia, and later Italy, the United States, and others) and the Central Powers (Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria).

More than 65 million men served in its armies. An estimated 16 million soldiers and civilians died. The fighting stopped with an armistice at 11 a.m. on November 11, 1918, and the Treaty of Versailles was signed on June 28, 1919.

Causes: MAIN and the Spark

Historians still argue about why the war began. A helpful starting point is the memory aid MAIN: four long-term pressures that turned Europe into a powder keg. None of them made war certain. Together, they made a small crisis very dangerous.

Militarism

The great powers built huge armies and drew up detailed war plans. Germany and Britain raced to build battleships. Generals believed the side that mobilized fastest would win, so leaders felt pressure to act quickly.

Alliances

Europe split into two armed camps. Alliances were meant to scare enemies into keeping the peace. Instead, they meant a quarrel between two countries could pull in all the others.

Imperialism

European powers competed for colonies and trade in Africa and Asia. Rivalries over empire, such as Germany's demand for "a place in the sun," fed suspicion and mistrust.

Nationalism

Intense pride in one's nation made people hungry for glory. In the Balkans, many South Slavs wanted to break free of Austria-Hungary, and Serbia hoped to unite them.

The spark: Sarajevo, June 28, 1914

Archduke Franz Ferdinand, heir to the throne of Austria-Hungary, was visiting Sarajevo, the capital of Bosnia. Austria-Hungary had annexed Bosnia in 1908, angering Serbian nationalists. That morning, a bomb thrown at his car missed. Later, his driver took a wrong turn. Gavrilo Princip, a 19-year-old Bosnian Serb, stepped forward and shot both the archduke and his wife, Sophie. Both died.

What followed is called the July Crisis. Austria-Hungary, with Germany's backing, sent Serbia a harsh ultimatum on July 23 and declared war on July 28. Russia mobilized to protect Serbia. Germany declared war on Russia (August 1) and France (August 3), then invaded neutral Belgium to reach France. On August 4, Britain declared war on Germany. In about five weeks, a murder had become a world war.

Two Alliances

By the end of 1915, two coalitions were at war. The dates show when each country entered.

The Allies

SerbiaAustria-Hungary declared war on it, July 28, 1914
RussiaAt war August 1, 1914; left the war in 1918
FranceAt war August 3, 1914
BelgiumInvaded August 4, 1914
Britain and its empire (including Canada, Australia, New Zealand, India, and South Africa)Declared war August 4, 1914
JapanDeclared war on Germany, August 1914
ItalyDeclared war on Austria-Hungary, May 23, 1915
United States (an "associated power")Declared war on Germany, April 6, 1917

The Central Powers

Austria-HungaryDeclared war on Serbia, July 28, 1914
GermanyDeclared war on Russia, August 1, 1914
Ottoman EmpireEntered after its navy raided Russia's Black Sea coast, October 29, 1914
BulgariaJoined in October 1915

Before the war, Italy had been allied with Germany and Austria-Hungary in the Triple Alliance. It stayed neutral in 1914, then switched sides.

Fronts and Battles

Germany's Schlieffen Plan aimed to defeat France in a few weeks by sweeping through Belgium, then turn east to fight Russia. It failed. Germany ended up fighting a two-front war: the Western Front in Belgium and France, and the Eastern Front against Russia. Other fronts opened in Italy, the Balkans, the Middle East, Africa, and at sea.

Map of Europe in World War I with approximate 1914 borders. Allied countries are shaded blue: Britain, France, Belgium, Russia, Serbia, and Montenegro, with Italy, Romania, Portugal, and Greece in a lighter blue because they joined later. The Central Powers, Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria, are shaded rose. Neutral countries such as Spain, Switzerland, the Netherlands, and Sweden are beige. A solid red line marks the Western Front from the Belgian coast to the Swiss border. A purple dashed line marks the Eastern Front inside the Russian Empire, from the Baltic Sea south to Romania. A short red dashed line marks the Italian Front in the Alps. Red markers show the battles of Jutland, Tannenberg, Verdun, Caporetto, and Gallipoli. A purple diamond marks Brest-Litovsk, where Russia signed its peace treaty. Black squares mark London, Paris, Berlin, Vienna, Sarajevo, Petrograd, and Constantinople. — Europe at war: the two alliances and the main fronts. Borders are approximate and show Europe in 1914, before the war changed them. Colonies outside Europe are not shaded. Front lines moved during the war, so the lines shown are approximate too. Original map drawn for Jugami from public-domain Natural Earth coastline data.

First Battle of the Marne

When: September 6–12, 1914
Where: East of Paris, France
Result: French and British stop the German advance

The Germans came so close to Paris that the French government left for Bordeaux. Then the French and British counterattacked and pushed them back. The Schlieffen Plan was dead. Paris taxis famously carried some soldiers to the front, but most went by train; the taxis mattered more for morale than for victory.

Tannenberg

When: August 26–30, 1914
Where: East Prussia (today in Poland)
Result: Crushing German victory over Russia

Russia invaded Germany sooner than Germany expected, but one of its armies was surrounded and destroyed. Russia kept fighting, and the Eastern Front became a long, costly struggle.

Gallipoli

When: April 25, 1915 – January 9, 1916
Where: Ottoman Empire, beside the Dardanelles strait
Result: Ottoman victory; the Allies withdraw

The Allies hoped to knock the Ottomans out of the war and open a sea route to Russia. Australian and New Zealand troops (ANZACs) landed on April 25, still remembered as Anzac Day. Nearly half a million Allied soldiers served there, and more than 220,000 became casualties. Ottoman losses were about as high. One Ottoman officer there, Mustafa Kemal, later founded modern Turkey.

Verdun

When: February 21 – December 18, 1916
Where: Verdun, northeastern France
Casualties: More than 700,000, French and German

Germany's commander wanted to "bleed France white" by attacking a place France would never give up. Both sides lost hundreds of thousands of men, and the front line barely moved. For the French, Verdun became a symbol of endurance: "They shall not pass."

The Somme

When: July 1 – November 18, 1916
Where: Somme River, northern France
Casualties: More than 1 million on all sides

A British and French offensive, meant partly to take pressure off Verdun. On the first day alone, the British Army had 57,470 casualties, including 19,240 killed, the worst day in its history. Tanks went into battle for the first time here, on September 15, 1916.

Jutland

When: May 31 – June 1, 1916
Where: North Sea, off Denmark
Result: Indecisive; the British blockade holds

The war's biggest clash of battleships. Britain lost more ships, but the German fleet went back to port and rarely came out again. Germany turned instead to submarine warfare.

Passchendaele (Third Ypres)

When: July 31 – November 10, 1917
Where: Near Ypres, Belgium
Result: Small Allied gains at huge cost

Heavy rain and shelling turned the battlefield into a swamp of mud. Its name became shorthand for the misery and waste of trench warfare.

Meuse-Argonne

When: September 26 – November 11, 1918
Where: Northeastern France
US troops: More than 1.2 million

The largest and deadliest battle in US history: 26,277 Americans were killed. It was part of the Allies' final "Hundred Days" push that ended the war.

Close-up map of Belgium and northern France. A thick red trench line runs from the North Sea coast of Belgium south past Ypres and the Somme, bends east past Verdun, and then runs south to the Swiss border. West of it is the Allied side, with Paris, Amiens, the Marne, and Compiègne, where the armistice was signed in 1918. East of it is German-held land, including Brussels. Switzerland is outlined with a dashed border at the southern end of the line. — The Western Front, about 1915–1917. For most of the war, the trench line moved only a few miles either way. The line is approximate. Original map drawn for Jugami from public-domain Natural Earth data.

Trenches and New Weapons

By the end of 1914, after the First Battle of Ypres, both sides on the Western Front had dug in. A line of trenches soon stretched from the North Sea coast to the Swiss border. Defending had become far easier than attacking: a few men with a machine gun behind barbed wire could stop a whole battalion crossing open ground.

A simplified trench system on the Western Front. Real trenches zigzagged so that an enemy who got in could not fire straight down the line. Original diagram drawn for Jugami; not to scale.

Machine guns

One machine gun could fire hundreds of bullets a minute. Attacking soldiers crossing no man's land were mowed down, which is a big reason why offensives cost so many lives.

Artillery

Huge guns fired shells for days before an attack. Shellfire caused most of the war's battlefield casualties and left craters everywhere. Soldiers who suffered breakdowns under constant shelling were said to have "shell shock."

Poison gas

Germany carried out the first large-scale chlorine gas attack at the Second Battle of Ypres, on April 22, 1915. Both sides soon used gas, including mustard gas, and soldiers carried gas masks.

Tanks

The British first sent tanks into battle at the Somme on September 15, 1916. Early tanks were slow and broke down often, but by 1918 they helped Allied troops break through.

Aircraft and airships

Planes began as scouts, spotting enemy positions. Soon pilots fought each other in "dogfights." German Zeppelin airships and later bomber planes dropped bombs on British cities.

Submarines (U-boats)

German U-boats tried to starve Britain by sinking ships bringing food and supplies. Attacks on ships carrying civilians, including Americans, angered the United States.

The Home Front

This was a total war: governments put entire nations, not just armies, to work for victory.

Conscription. Most countries drafted men into the army. Britain began conscription in 1916. The US passed the Selective Service Act on May 18, 1917.
Women at work. With millions of men away, women took jobs in factories, farms, offices, and transport. Hundreds of thousands of British women made shells in munitions factories. Their war work strengthened the case for women's right to vote in several countries after the war.
Propaganda. Posters, films, and newspapers urged people to enlist, buy war bonds, and hate the enemy. In the US, the Committee on Public Information ran the campaign.
Rationing. Blockades and U-boats caused shortages. Britain introduced rationing of some foods in 1918. In Germany, the British naval blockade caused severe hunger.
Limits on free speech. In the US, the Espionage Act (June 15, 1917) and the Sedition Act (May 16, 1918) made it a crime to interfere with the war effort; some people were jailed for speaking against the war.
A war of empires. Britain and France brought in soldiers and workers from their colonies and dominions, including India, Africa, Southeast Asia, and Canada, Australia, and New Zealand.

1917: America In, Russia Out

Why the United States entered the war

President Woodrow Wilson kept the US neutral for almost three years. Several events pulled it in:

The Lusitania. On May 7, 1915, a German U-boat sank this British passenger liner. Of the 1,198 people who died, 128 were Americans.
Unrestricted submarine warfare. On February 1, 1917, Germany announced it would sink any ship near Britain without warning, including neutral American ships. The US broke off diplomatic relations on February 3.
The Zimmermann Telegram. In January 1917, Germany's foreign secretary secretly proposed that if the US entered the war, Mexico should join Germany and win back Texas, New Mexico, and Arizona. British codebreakers decoded it and passed it to the US; it was published on March 1, 1917, and Americans were outraged.

On April 2, 1917, Wilson asked Congress to declare war. The Senate voted 82–6 and the House 373–50, and the US declared war on Germany on April 6, 1917. About 2 million American soldiers of the American Expeditionary Forces (AEF), led by General John J. Pershing, reached France. Their fresh numbers helped tip the balance in 1918.

Revolution in Russia

Russia had suffered huge losses, food shortages, and poor leadership. In early 1917, strikes and riots broke out in Petrograd (St. Petersburg). Soldiers joined the protesters, and Tsar Nicholas II abdicated on March 15, 1917, ending more than 300 years of Romanov rule. A Provisional Government kept fighting the war, which made it unpopular.

Vladimir Lenin and his Bolsheviks promised "peace, land, and bread." On November 7, 1917, they seized power. The new government signed the Treaty of Brest-Litovsk with Germany on March 3, 1918, giving up huge territories to leave the war. Russia then fell into a bloody civil war. In July 1918 Bolsheviks murdered the former tsar and his family.

1918: The Endgame

With Russia out, Germany moved troops west and launched its Spring Offensive on March 21, 1918, hoping to win before the Americans arrived in force. It gained ground but ran out of men and supplies. The Allies, now under one supreme commander, the French general Ferdinand Foch, stopped the Germans at the Second Battle of the Marne (July 15 – August 6, 1918).

On August 8, 1918, the Allies attacked near Amiens. A German commander, Erich Ludendorff, called it "the black day of the German Army." It began the Hundred Days Offensive, a string of Allied victories. Germany's allies collapsed one by one, its navy mutinied, and revolution spread at home. Kaiser Wilhelm II abdicated on November 9, 1918.

Before dawn on November 11, 1918, German representatives signed an armistice (a ceasefire) in Foch's railway carriage in the forest of Compiègne, France. The guns fell silent at 11 a.m.: the eleventh hour of the eleventh day of the eleventh month. Many countries still mark November 11 as Armistice Day, Remembrance Day, or, in the US, Veterans Day.

Versailles and Its Legacy

The Paris Peace Conference opened on January 18, 1919. It was dominated by the Big Four: Woodrow Wilson (US), David Lloyd George (Britain), Georges Clemenceau (France), and Vittorio Orlando (Italy). Germany was not allowed to negotiate.

Wilson arrived with his Fourteen Points (January 8, 1918), a plan for a fair peace: open diplomacy, freedom of the seas, lower trade barriers, smaller armies, self-determination for peoples, and a League of Nations. Clemenceau, whose country had been invaded and devastated, wanted Germany punished and kept weak. The treaty became a compromise that satisfied almost no one. Germany signed the Treaty of Versailles in the Hall of Mirrors on June 28, 1919, five years to the day after the Sarajevo assassination.

Key terms of the Treaty of Versailles for Germany
Term	What it meant
War guilt (Article 231)	Germany accepted responsibility for the loss and damage of the war. Germans bitterly called it the "war guilt clause."
Reparations	Germany had to pay for war damage. In 1921 the bill was set at 132 billion gold marks.
Military limits	The army was capped at 100,000 men. Germany could have no air force, tanks, or submarines.
The Rhineland	German land along the Rhine River was demilitarized (no troops allowed), and Allied troops occupied it.
Lost territory	Alsace-Lorraine went back to France; land went to a newly independent Poland; Germany lost all its overseas colonies.
League of Nations	A new international body to settle disputes peacefully. It began on January 10, 1920. Germany was at first left out.

Other treaties dealt with Austria, Hungary, Bulgaria, and the Ottoman Empire (the Treaty of Sèvres, August 10, 1920).

Four empires fell

The German, Austro-Hungarian, Russian, and Ottoman empires all collapsed. New nations appeared on the map, including Poland, Czechoslovakia, Austria, Hungary, the Baltic states, and the kingdom later called Yugoslavia.

The US says no

The US Senate rejected the treaty twice, on November 19, 1919, and March 19, 1920. The United States never joined the League of Nations that Wilson had championed, which weakened it from the start.

A new Middle East

The secret Sykes-Picot Agreement (1916) and the postwar settlement divided former Ottoman lands into British and French "mandates," including Iraq, Syria, Lebanon, and Palestine. Arab leaders who had been promised independence felt betrayed, and many of today's borders date from this time.

The road to another war

Many Germans felt humiliated by the treaty. Some believed the false "stab-in-the-back" myth that Germany had not really lost on the battlefield but had been betrayed at home. Anger over Versailles, plus economic crisis, helped Adolf Hitler rise to power. Just 20 years later, World War II began.

People to Know

Allies

Woodrow WilsonUS president; Fourteen Points; League of Nations
Georges ClemenceauFrench prime minister who wanted a harsh peace
David Lloyd GeorgeBritish prime minister from 1916
Ferdinand FochFrench general; supreme Allied commander in 1918
John J. PershingCommander of the American Expeditionary Forces
Nicholas IILast tsar of Russia; abdicated 1917
Vladimir LeninBolshevik leader; took Russia out of the war

Central Powers

Wilhelm IIGerman kaiser (emperor); abdicated November 9, 1918
Franz JosephEmperor of Austria-Hungary; died in 1916
Franz FerdinandHeir to Austria-Hungary's throne; assassinated 1914
Paul von HindenburgGerman general; victor at Tannenberg; later army chief
Erich LudendorffGerman general who planned the 1918 Spring Offensive
Mustafa KemalOttoman officer at Gallipoli; later founder of modern Turkey

Gavrilo Princip, the assassin, belonged to no army: he was a Bosnian Serb nationalist linked to a secret Serbian society, the Black Hand.

Interactive Timeline

Follow the war from the spark in Sarajevo to the peace treaties. Use the buttons to show one kind of event or one year at a time.

Jun 28, 1914 · Assassination in SarajevoOutbreak
Gavrilo Princip shoots Archduke Franz Ferdinand and his wife, Sophie.
Jul 23, 1914 · Ultimatum to SerbiaOutbreak
Austria-Hungary, backed by Germany, sends Serbia demands designed to be hard to accept.
Jul 28, 1914 · Austria-Hungary declares war on SerbiaOutbreak
Russia begins to mobilize in support of Serbia.
Aug 1, 1914 · Germany declares war on RussiaOutbreak
Two days later, on August 3, Germany declares war on France.
Aug 4, 1914 · Britain declares war on GermanyOutbreak
Germany has invaded neutral Belgium on its way to France.
Aug 26–30, 1914 · Battle of TannenbergOther fronts and sea · Eastern Front
Germany destroys a Russian army in East Prussia.
Sep 6–12, 1914 · First Battle of the MarneWestern Front
The Allies stop the German advance near Paris. The Schlieffen Plan fails.
Oct–Nov 1914 · First Battle of YpresWestern Front
Both sides dig in. Trenches soon run from the North Sea to Switzerland.
Oct 29, 1914 · The Ottoman Empire enters the warOther fronts and sea · Ottoman Empire
Ottoman warships raid Russia's Black Sea coast. Russia, Britain, and France declare war in early November.
Dec 25, 1914 · The Christmas TruceWestern Front
In some places, British and German soldiers stop fighting and meet in no man's land.
Apr 22, 1915 · First large-scale gas attackWestern Front
Germany releases chlorine gas at the Second Battle of Ypres.
Apr 25, 1915 · Gallipoli landingsOther fronts and sea · Gallipoli
Allied troops, including ANZACs, land on the Gallipoli peninsula.
May 7, 1915 · The Lusitania is sunkUnited States
A German U-boat sinks the British liner; 1,198 die, including 128 Americans.
May 23, 1915 · Italy joins the AlliesOther fronts and sea · Italian Front
Italy declares war on Austria-Hungary, opening a front in the Alps.
Oct 1915 · Bulgaria joins the Central PowersOther fronts and sea · Balkans
Serbia is soon overrun.
Jan 9, 1916 · Last Allied troops leave GallipoliOther fronts and sea · Gallipoli
The campaign ends in Ottoman victory.
Feb 21, 1916 · Battle of Verdun beginsWestern Front
It lasts until December 18 and costs more than 700,000 casualties.
May 16, 1916 · Sykes-Picot AgreementPeace · Middle East
Britain and France secretly plan how to divide Ottoman lands after the war.
May 31–Jun 1, 1916 · Battle of JutlandOther fronts and sea · North Sea
The war's largest naval battle. The British blockade of Germany holds.
Jul 1, 1916 · Battle of the Somme beginsWestern Front
The British Army suffers 57,470 casualties on the first day. Tanks appear on September 15.
Feb 1, 1917 · Unrestricted submarine warfareUnited States
Germany will sink ships without warning. The US breaks off relations on February 3.
Mar 1, 1917 · Zimmermann Telegram publishedUnited States
Americans learn Germany offered Mexico an alliance against the US.
Mar 15, 1917 · Tsar Nicholas II abdicatesRussia
The February Revolution ends Romanov rule. A Provisional Government takes over.
Apr 6, 1917 · The US declares war on GermanyUnited States
Four days after President Wilson's war message to Congress.
Jul 31, 1917 · Passchendaele beginsWestern Front
Months of fighting in deep mud near Ypres, until November 10.
Nov 7, 1917 · Bolsheviks seize powerRussia
Lenin's October Revolution (October 25 on Russia's old calendar).
Jan 8, 1918 · Wilson's Fourteen PointsPeace
Wilson lays out his plan for peace, including a League of Nations.
Mar 3, 1918 · Treaty of Brest-LitovskRussia
Russia leaves the war, giving up huge territories to Germany.
Mar 21, 1918 · German Spring OffensiveWestern Front
Germany's last big gamble to win before American troops arrive in force.
Jul 15, 1918 · Second Battle of the MarneWestern Front
The Allies, with American help, stop the last German offensive.
Aug 8, 1918 · Battle of AmiensWestern Front
"The black day of the German Army." The Hundred Days Offensive begins.
Sep 26, 1918 · Meuse-Argonne Offensive beginsUnited States
More than 1.2 million Americans fight in the deadliest battle in US history.
Nov 9, 1918 · Kaiser Wilhelm II abdicatesPeace · Germany
Revolution spreads in Germany, and the kaiser flees to the Netherlands.
Nov 11, 1918 · The ArmisticePeace
Signed at Compiègne before dawn; the fighting stops at 11 a.m.
Jan 18, 1919 · Paris Peace Conference opensPeace
The Big Four lead the talks; Germany is not invited to negotiate.
Jun 28, 1919 · Treaty of Versailles signedPeace
Five years to the day after the Sarajevo assassination.
Nov 19, 1919 · US Senate rejects the treatyUnited States
It fails again on March 19, 1920. The US never joins the League.
Jan 10, 1920 · League of Nations beginsPeace
The world's first major international peace organization comes into being.

Primary Sources

A primary source was made by people who lived through the events. Read each one closely and ask: Who made this? When? Why? Who was the audience?

In Flanders fields the poppies blow
Between the crosses, row on row,
That mark our place; and in the sky
The larks, still bravely singing, fly
Scarce heard amid the guns below.

We are the Dead. Short days ago
We lived, felt dawn, saw sunset glow,
Loved and were loved, and now we lie,
In Flanders fields.

Take up our quarrel with the foe:
To you from failing hands we throw
The torch; be yours to hold it high.
If ye break faith with us who die
We shall not sleep, though poppies grow
In Flanders fields.

John McCrae, "In Flanders Fields," written May 3, 1915, near Ypres, Belgium; first published in Punch, December 8, 1915. Text from In Flanders Fields and Other Poems, Project Gutenberg eBook #353. Public domain.

Why it matters: McCrae, a Canadian army doctor, wrote this the day after his friend Alexis Helmer was killed. The poem made the red poppy the symbol of remembrance for the war dead.

Think: Who is speaking in the poem? What do the dead ask the living to do, and how might a soldier and a grieving parent read that request differently?

"The world must be made safe for democracy. Its peace must be planted upon the tested foundations of political liberty. We have no selfish ends to serve. We desire no conquest, no dominion."

President Woodrow Wilson, address to a joint session of Congress asking for a declaration of war against Germany, April 2, 1917. Text from the National Archives, Milestone Documents. Public domain.

Why it matters: Wilson presented the war not as a fight for land or revenge but as a crusade for democracy. Four days later, the US declared war.

Think: Wilson's ally Russia had just overthrown its tsar. Why might that have made this argument easier to make in April 1917 than a year earlier?

"A general association of nations must be formed under specific covenants for the purpose of affording mutual guarantees of political independence and territorial integrity to great and small states alike."

President Woodrow Wilson, the Fourteen Points, Point XIV, address to Congress, January 8, 1918. Text from the Avalon Project, Yale Law School. Public domain.

Why it matters: This point became the League of Nations, the ancestor of today's United Nations.

Think: What does "great and small states alike" promise? Why might small nations, and empires' colonies, have found that exciting?

"The Allied and Associated Governments affirm and Germany accepts the responsibility of Germany and her allies for causing all the loss and damage to which the Allied and Associated Governments and their nationals have been subjected as a consequence of the war imposed upon them by the aggression of Germany and her allies."

Treaty of Versailles, Part VIII (Reparation), Article 231, signed June 28, 1919. Text from the Avalon Project, Yale Law School. Public domain.

Why it matters: The article was the legal basis for reparations. Germans called it the "war guilt clause," and resentment of it fed German nationalism in the 1920s and 1930s.

Think: Compare this with Wilson's words above. Does Article 231 sound like "no selfish ends"? Why or why not?

Vocabulary

Militarism: A belief in building strong armed forces and being ready to use them.
Alliance: An agreement between nations to support each other, especially in war.
Imperialism: When a powerful country takes control of other lands and peoples.
Nationalism: Strong pride in and loyalty to one's nation or people.
Ultimatum: A final set of demands; refusing them leads to serious consequences.
Mobilize: To get an army ready for war by calling up soldiers and moving them into position.
Schlieffen Plan: Germany's plan to defeat France quickly through Belgium, then fight Russia.
Stalemate: A situation where neither side can win or make progress.
No man's land: The deadly ground between the two sides' front-line trenches.
Total war: A war in which a nation uses all its people and resources to win.
Propaganda: Information spread to persuade people, often one-sided or misleading.
Conscription: A required military draft.
U-boat: A German submarine (from Unterseeboot, "undersea boat").
Armistice: An agreement to stop fighting while peace terms are worked out.
Reparations: Payments a defeated nation must make for war damage.
Self-determination: The right of a people to choose their own government.

Quiz: Test Yourself

Ten questions. Choose an answer for each, then press Check my answers to see your score and an explanation for every question.

1. What event sparked the July Crisis of 1914? A. Germany's invasion of Belgium B. The sinking of the British passenger liner Lusitania by a U-boat C. The assassination of Archduke Franz Ferdinand D. Russia's revolution against the tsar

2. In the memory aid MAIN, what does the "A" stand for? A. Alliances B. Armistice C. Assassination D. Artillery

3. What action led Britain to declare war on Germany? A. The Zimmermann Telegram B. A German gas attack on London C. Germany's secret alliance with Italy and Austria-Hungary D. Germany's invasion of neutral Belgium

4. Why did the Western Front become a stalemate for most of the war? A. Both armies ran completely out of trained soldiers by early 1915 B. Weapons like machine guns gave defenders a big advantage C. The generals agreed not to attack D. Winter weather stopped all fighting each year

5. The British Army's deadliest single day came at the start of which battle? A. Gallipoli B. Tannenberg C. Jutland D. The Somme

6. What did the Zimmermann Telegram propose? A. That the US and Germany sign a peace treaty B. That Russia leave the war and sign a separate peace with Germany right away C. That Mexico join Germany in a war against the United States D. That Britain end its naval blockade

7. How did Russia leave the war? A. The Bolshevik government signed the Treaty of Brest-Litovsk B. The tsar won a final victory at Tannenberg C. The Allies released Russia from the war at the Paris Peace Conference in 1919 D. Russia switched to the Central Powers

8. When did the armistice end the fighting? A. June 28, 1919 B. November 11, 1918 C. April 6, 1917 D. March 3, 1918

9. Which of these was part of the Treaty of Versailles? A. Germany was split into four zones, each run by one of the Big Four powers B. Germany received Alsace-Lorraine from France C. Germany's army was allowed to grow to 1 million men D. Germany accepted responsibility for the war's loss and damage

10. Why did the United States never join the League of Nations? A. The US Senate rejected the Treaty of Versailles B. Germany vetoed American membership C. Wilson decided the League was a bad idea D. The League refused membership to every country outside of Europe

Talk About It

Which MAIN cause do you think mattered most? Could the assassination have led to a world war without it?
Generals kept ordering attacks across no man's land even after huge losses. What pressures might have pushed them to do that?
Compare Wilson's "safe for democracy" speech with Article 231. Did the peace live up to the promises made during the war?
How did the war change life for people who never saw a battlefield, such as women in factories, colonial soldiers, or Armenian families?
Herodotus wrote so that the causes of war "may be remembered." What lessons from World War I do you think the world should remember?

Works Cited and Further Reading

Imperial War Museums. "What Happened at the Somme," "Voices of the First World War: The Christmas Truce," and related First World War articles. iwm.org.uk/history/first-world-war
National WWI Museum and Memorial. "WWI Timeline" and "Key Dates." theworldwar.org/learn/wwi
Encyclopaedia Britannica. "World War I," "First Battle of the Marne," and "Battle of Verdun." britannica.com/event/World-War-I
National Army Museum (UK). "Gallipoli." nam.ac.uk/explore/gallipoli
US Department of State, Office of the Historian. "American Entry into World War I, 1917" and "The Paris Peace Conference and the Treaty of Versailles." history.state.gov/milestones/1914-1920
National Archives (US). "President Woodrow Wilson's Address to Congress Requesting a Declaration of War Against Germany (1917)." archives.gov
The Avalon Project, Yale Law School. "President Woodrow Wilson's Fourteen Points" and "Treaty of Versailles, Part VIII." avalon.law.yale.edu
United States Senate. "The Senate Votes on the Treaty of Versailles." senate.gov
Library of Congress. "World War I: American Experiences" and related research guides. loc.gov
United States Holocaust Memorial Museum. "The Armenian Genocide (1915–16): Overview." encyclopedia.ushmm.org
Centers for Disease Control and Prevention. "1918 Pandemic (H1N1 virus)." cdc.gov
McCrae, John. In Flanders Fields and Other Poems. Project Gutenberg eBook #353. gutenberg.org/ebooks/353
Herodotus. The History of Herodotus, Vol. 1, translated by G. C. Macaulay. Project Gutenberg eBook #2707. gutenberg.org/ebooks/2707

Credits: All illustrations, diagrams, and maps on this page are original artwork made for Jugami. Map coastlines are based on public-domain Natural Earth data; front lines are approximate. Casualty figures for this war vary by source; we give the estimates of the institutions cited above.