A state that emerged from the territory or political collapse of an earlier state or empire, such as Austria, Hungary, or Czechoslovakia.

A group that differs by ethnicity, language, religion, or nationality from the majority within a state and may seek legal protection or political change.

A League of Nations arrangement that placed former German or Ottoman territories under administration by another power, supposedly as temporary supervision.

A direct vote by residents on a political question, often used to determine sovereignty or a border.

Armed conflict between groups within the same country or former state, usually over political power or territory.

A direct vote by residents on a political issue, especially sovereignty or a territorial border.

What is mandate system?

The League of Nations system that assigned administration of certain former German and Ottoman territories to victorious powers after World War I.

What is Weimar Republic?

The German republic established after the fall of the German Empire in 1918.

Empires Fall and New States Rise — World War I: A Global War and Its Lasting Aftermath

1. Start with the Map: Four Empires Unravel

A World That Did Not Return

The Armistice of November 1918 stopped major fighting, but it did not restore the prewar order. Four multiethnic empires collapsed: Russian, German, Austro-Hungarian, and Ottoman.

Why Collapse Mattered

Imperial governments had ruled many peoples. When authority weakened, revolutions, independence movements, border wars, and competing territorial claims followed.

The Core Tension

National self-determination promised political choice for peoples, but populations were mixed together. Borders could not neatly place every nationality inside its preferred state.

2. Use a Three-Step Method to Analyze Imperial Collapse

Step 1: Identify the Empire

Ask which imperial state ruled the territory before 1918. This reveals the administrative borders, institutions, and power structures that shaped the postwar crisis.

Step 2: Identify the Claimants

List groups seeking power: national movements, local minorities, revolutionary parties, and neighboring governments. More than one claimant may have a plausible case.

Step 3: Test the Border

Compare the new boundary with where people lived. A state could fulfill self-determination for one majority while leaving another population as a minority.

3. Russia: Revolution, Civil War, and New Republics

Revolution Ends Tsarist Rule

The February Revolution of 1917 removed Tsar Nicholas II. The Bolsheviks then seized power in the October Revolution, transforming a wartime crisis into a struggle over political order.

Civil War and Separation

Civil war from 1918 to 1922 involved Bolshevik Reds, anti-Bolshevik Whites, and regional movements. Finland, Estonia, Latvia, Lithuania, and Poland emerged outside Soviet control.

A New Union

Bolshevik victory led to the creation of the USSR in December 1922. The Russian Empire did not simply become Russia again; it was replaced by a new Soviet federal state.

4. Austria-Hungary: One Empire, Many Successor States

An Empire of Many Peoples

Austria-Hungary contained numerous national communities. Its collapse in late 1918 released national movements that had been constrained within one imperial political system.

Successor States

Austria, Hungary, and Czechoslovakia emerged, while the Kingdom of Serbs, Croats, and Slovenes united South Slav lands. Poland, Romania, and Italy also gained territory.

Trianon and Minority Questions

The Treaty of Trianon in 1920 reduced Hungary sharply. Millions of ethnic Hungarians lived beyond Hungary's new borders, showing why a border settlement could satisfy some groups while angering others.

5. Germany: Imperial Regime Falls, German State Continues

Monarchy to Republic

The German Empire ended when Kaiser Wilhelm II abdicated on November 9, 1918. The Weimar Republic replaced imperial monarchy after defeat and revolution.

Borders Changed, Germany Remained

Unlike Austria-Hungary, Germany remained a unified state. But the Treaty of Versailles in 1919 transferred territory, removed colonies, and created politically sensitive border arrangements.

6. Ottoman Collapse and the New Middle East

Mandates, Not Immediate Independence

Former Ottoman Arab provinces were placed under League of Nations mandates. Britain governed Iraq and Palestine, while France governed Syria and Lebanon.

What a Mandate Meant in Practice

Mandates were described as temporary supervision, but British and French authorities exercised extensive control. This differed from full national self-government.

Turkey Rejects Partition

The Treaty of Sevres of 1920 proposed extensive partition. Turkish nationalists defeated these plans, and the Treaty of Lausanne in 1923 recognized the Republic of Turkey.

7. Border-Maker Challenge: Draw a Fair Line

Thought Exercise: Can One Border Be Fair to Everyone?

You are designing a border after World War I. A region has 100,000 people:

55,000 identify with Nation A and live mostly in the west
30,000 identify with Nation B and live mostly in the east
15,000 identify with Nation C and live in scattered towns across the region

Your task

Choose one option, then explain its strongest benefit and biggest drawback.

Give the entire region to Nation A.
Divide the region between Nations A and B.
Create an autonomous region with protections for all three groups.
Hold a local plebiscite, or vote, district by district.

Check your reasoning

Use these questions:

Does your plan follow majority rule?
What happens to minorities left on the other side of the border?
Could dividing the region cut railways, farms, or cities apart?
Who would enforce minority rights?

There is no friction-free answer. This is why the post-1918 settlement produced both new states and new conflicts.

8. Poland Shows Why Borders Became Flashpoints

Poland Returns

Poland regained independence in 1918 after partitions by Russia, Prussia/Germany, and Austria-Hungary. Restoring Poland was a major act of national self-determination.

One State, Several Conflicts

Poland fought Soviet Russia, contested Upper Silesia with Germany, and depended economically on access near Danzig. Each dispute involved mixed populations and strategic interests.

The Broader Lesson

Plebiscites and international administration offered partial solutions, not perfect ones. The postwar map created new national states but also left many people as minorities.

9. Flashcards: Essential Vocabulary

Review the Key Terms

Flip each card, then connect the term to one example from the post-1918 settlement.

National self-determination: The principle that peoples should be able to choose their political status and government. After World War I, applying it was difficult because populations were mixed.
Successor state: A state that emerged from the territory or political collapse of an earlier state or empire, such as Austria, Hungary, or Czechoslovakia.
Minority population: A group that differs by ethnicity, language, religion, or nationality from the majority within a state and may seek legal protection or political change.
Mandate: A League of Nations arrangement that placed former German or Ottoman territories under administration by another power, supposedly as temporary supervision.
Plebiscite: A direct vote by residents on a political question, often used to determine sovereignty or a border.
Weimar Republic: Germany's republican government from 1918 to 1933, created after the fall of the German Empire.

10. Check Understanding: Self-Determination in Practice

Choose the Best Answer

Which statement best explains why post-World War I borders remained contentious even when leaders supported national self-determination?

Most regions contained only one national group, so border disputes were mainly caused by mapmaking errors.
Ethnic, linguistic, religious, and economic communities often overlapped, so creating a state for one group could leave other groups as minorities.
The peace treaties abolished all former empires immediately and gave every territory independence.
The League of Nations refused to recognize any new states after 1918.

Show Answer

Answer: B) Ethnic, linguistic, religious, and economic communities often overlapped, so creating a state for one group could leave other groups as minorities.

This is correct because populations were rarely separated into neat territorial blocks. New borders could advance one group's national goals while placing another group under a government it did not identify with. Strategic resources, transport routes, and historic claims intensified the problem.

Key Terms

civil war: Armed conflict between groups within the same country or former state, usually over political power or territory.
plebiscite: A direct vote by residents on a political issue, especially sovereignty or a territorial border.
mandate system: The League of Nations system that assigned administration of certain former German and Ottoman territories to victorious powers after World War I.
Weimar Republic: The German republic established after the fall of the German Empire in 1918.
successor state: A state that emerges from the territory or political collapse of an earlier state or empire.
Treaty of Trianon: The 1920 peace treaty with Hungary that set Hungary's postwar borders after the collapse of Austria-Hungary.
Treaty of Lausanne: The 1923 treaty that recognized the sovereignty of the Republic of Turkey and replaced the unratified Treaty of Sevres.
minority population: A group within a state that differs from the majority by nationality, ethnicity, language, religion, or another identity.
Austro-Hungarian Empire: A multiethnic Central European empire ruled by the Habsburg dynasty until its collapse in 1918.
national self-determination: The principle that peoples should be able to determine their political status and choose their government.