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NotesHistoryTopic 3.2German expansion and the outbreak of war (1938–1939)
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3.2.43 min read

German expansion and the outbreak of war (1938–1939)

IB History • Unit 3

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Contents

  • The road to September 1939
  • From Czechoslovakia to the invasion of Poland
  • Paper 1 skills: why war broke out in 1939

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The big idea: When Hitler seized all of Czechoslovakia, he killed appeasement. Britain and France finally drew a line, so his next grab, Poland, meant war.

Back in September 1938, the Munich Agreement had handed Germany the Sudetenland, the German-speaking edge of Czechoslovakia. In return Hitler promised this was his very last demand, and for a few months people wanted to believe him.

Then in March 1939 he simply broke that promise and marched his troops in to take the rest of Czechoslovakia. This time the land was not German-speaking, so his old excuse about only wanting Germans made no sense at all.

That was the moment Britain and France stopped trusting Hitler. They decided appeasement had failed, so they publicly guaranteed Poland's independence, warning that an attack on Poland would mean war.

Hitler still wanted Poland, but he had one big fear: fighting Britain and France in the west and the USSR in the east at the same time. To avoid that, in August 1939 he made a shock deal with his enemy Stalin, the Nazi-Soviet Pact, which secretly agreed to split Poland between them.

With the USSR no longer a threat, Germany invaded Poland on 1 September 1939. Two days later, on 3 September 1939, Britain and France kept their promise and declared war.

Memory hook: Remember the 1939 dominoes as C-G-P: Czechoslovakia seized, Guarantee to Poland given, Pact with the USSR signed, then Poland was invaded and war began.

Now follow the chain step by step, because in the exam you will be asked why these events led to war. Each move raised the stakes a little higher until war was almost impossible to avoid.

1

March 1939 — Hitler takes Prague

German troops marched into Prague and seized the rest of Czechoslovakia. Because this was not a German-speaking area, it proved Hitler's earlier promises were lies and finally ended appeasement.

2

March 1939 — the guarantee to Poland

Hitler now demanded Danzig, a port taken from Germany after 1918, plus a road across the Polish Corridor. Britain and France answered by guaranteeing Poland, warning that an attack meant war.

3

May 1939 — the Pact of Steel

Germany and Fascist Italy signed the Pact of Steel, a full military alliance promising to back each other in war. This showed Hitler's growing confidence that no one would stop him.

4

23 Aug 1939 — the Nazi-Soviet Pact

Germany and the USSR promised not to attack each other, and a secret part of the deal divided Poland between them. This freed Hitler from a two-front war and left Poland trapped.

5

1 Sept 1939 — Poland invaded

German forces poured into Poland. Britain and France declared war on 3 September, and the European war had begun.

Prague, Poland, Pact, Poland again: each step made war harder to escape.

Long-term causes vs short-term triggers: Long-term causes built up for years: anger over the Treaty of Versailles losing Danzig and the Corridor, Hitler's dream of Lebensraum in the east, and a League of Nations too weak to stop him.

Short-term triggers happened fast in 1939: seizing Czechoslovakia ended appeasement in March, the Nazi-Soviet Pact removed the USSR in August, and the invasion of Poland forced Britain and France to act in September.
DateEventWhy it mattered
Sept 1938Munich AgreementGermany gains the Sudetenland; Hitler promises no more demands
March 1939Occupation of CzechoslovakiaBroke the Munich promise and ended appeasement
March 1939British and French guarantee to PolandMade any attack on Poland risk war
May 1939Pact of SteelTied Italy to Germany militarily
23 Aug 1939Nazi-Soviet PactRemoved the two-front fear and secretly split Poland
1 Sept 1939Invasion of PolandThe direct trigger of war
3 Sept 1939Britain and France declare warThe European war begins
Why the Pact shocked the world: Nazis and Communists had spent years calling each other deadly enemies, so a friendly deal between Hitler and Stalin stunned everyone who saw it.

For Hitler it was never real friendship. It was a cold, temporary trick to crush Poland first and deal with the USSR later, which is exactly what he did when he invaded the Soviet Union in 1941.

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How this is tested (Paper 1): Paper 1 is the source paper, so you read documents and answer set questions on them. Sources here are often Hitler's speeches, diplomatic messages, or cartoons mocking the Nazi-Soviet Pact.

The classic trap on the 4-mark OPVL question is calling a source simply 'good' or 'bad' instead of using its origin and purpose to weigh both its value AND its limits.
IB-style questionEvaluate[9 marks]

Evaluate the significance of the Nazi-Soviet Pact (August 1939) in the outbreak of war in 1939.

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Common mistakes: Do not say Britain declared war over Czechoslovakia. War came over Poland in September 1939.

Do not call the Nazi-Soviet Pact an alliance. It was a non-aggression pact with a secret protocol. And keep the two dates straight: the invasion was 1 September, the declaration of war was 3 September 1939.

IB Exam Questions on German expansion and the outbreak of war (1938–1939)

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How German expansion and the outbreak of war (1938–1939) Appears in IB Exams

Examiners use specific command terms when asking about this topic. Here's what to expect:

Define

Give the precise meaning of key terms related to German expansion and the outbreak of war (1938–1939).

AO1
Describe

Give a detailed account of processes or features in German expansion and the outbreak of war (1938–1939).

AO2
Explain

Give reasons WHY — cause and effect within German expansion and the outbreak of war (1938–1939).

AO3
Evaluate

Weigh strengths AND limitations of approaches in German expansion and the outbreak of war (1938–1939).

AO3
Discuss

Present arguments FOR and AGAINST with a balanced conclusion.

AO3

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3.2.3Italian expansion (1935–1940)
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Collective security and appeasement (1933–1940)3.2.5

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