The outbreak of the First World War

Paper 2 SL & HL 2028 course 1914–1918 Sarajevo, Bosnia World history topic 11

How an assassination in Sarajevo turned into a general European war within six weeks — and why historians still argue about who was responsible.

Key questions

  1. What were the long-term causes of tension between the great powers before 1914?
  2. Why did the July Crisis of 1914 lead to a general war rather than a local one?
  3. How far should Germany be held responsible for the outbreak of war?

Overview

On 28 June 1914 Gavrilo Princip, a Bosnian Serb linked to the Serbian nationalist Key term · 1911–1917 Black Hand A secret Serbian nationalist society, led by army officers, that aimed to unite all Serbs — including those in Austria-Hungary — in a Greater Serbia. Why it matters It armed and trained the young Bosnian Serbs who assassinated Franz Ferdinand, giving Austria-Hungary its grounds to blame Serbia. See in glossary → , shot Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, in Sarajevo. Five weeks later the great powers of Europe were at war. Explaining how a regional crisis became a continental war means looking at both long-term tensions and the decisions made during the Key term · July 1914 July Crisis The month of diplomacy and decisions between the assassination in Sarajevo and the outbreak of general war. Why it matters It is where long-term tensions became war. Analysing each power's decisions during these weeks is essential to any argument about responsibility. See in glossary → .

Key dates

  1. 1882
    Germany, Austria-Hungary and Italy form the Key term · 1882–1915 Triple Alliance The defensive alliance of Germany, Austria-Hungary and Italy. Why it matters It bound Germany to Austria-Hungary's fate in the Balkans. Italy stayed neutral in 1914 and joined the other side in 1915, showing the limits of pre-war alliances. See in glossary → .
  2. 1894–1907
    France and Russia ally (1894); Britain settles its differences with France (1904) and Russia (1907), forming the Key term · 1907–1917 Triple Entente The informal alignment of France, Russia and Britain, built from the Franco-Russian alliance (1894), the Entente Cordiale (1904) and the Anglo-Russian Entente (1907). Why it matters Germany saw it as encirclement. Britain's commitments were looser than a formal alliance — which is why Belgium, not the Entente, decided its entry into the war. See in glossary → .
  3. 1906
    Britain launches HMS Dreadnought, intensifying the Key term · 1898–1912 Anglo-German naval race The competition between Britain and Germany to build battleships, intensified by Britain's launch of HMS Dreadnought in 1906. Why it matters It convinced Britain that Germany was a threat and pushed it towards France and Russia, although by 1912 Britain had clearly won the race. See in glossary → with Germany.
  4. 1908–1913
    Crises over Bosnia (1908), Morocco (1911) and the Key term · 1912–1913 Balkan Wars Two wars in which the Balkan states first drove the Ottoman Empire out of most of Europe and then fought each other over the spoils. Why it matters Serbia doubled in size and confidence, convincing Austria-Hungary's leaders that Serbian nationalism threatened their empire's survival. See in glossary → (1912–13).
  5. 28 Jun 1914
    Franz Ferdinand is assassinated in Sarajevo.
  6. 5–6 Jul 1914
    Germany gives Austria-Hungary the Key term · 5–6 July 1914 Blank cheque Germany's assurance to Austria-Hungary that it would support whatever action Vienna took against Serbia. Why it matters Historians who stress German responsibility see it as the key decision of the July Crisis, since it emboldened Austria-Hungary to risk war with Russia. See in glossary → .
  7. 23 Jul 1914
    Austria-Hungary sends Serbia an ultimatum designed to be rejected.
  8. 28–30 Jul 1914
    Austria-Hungary declares war on Serbia; Russia orders general mobilisation.
  9. 1–4 Aug 1914
    Germany declares war on Russia and France and invades Belgium; Britain declares war on Germany.

Long-term causes

Alliances. Two armed blocs faced each other. The alliances were defensive on paper, but they meant a conflict involving one great power was likely to draw in others — and they gave Germany a fear of “encirclement” by France and Russia.

Militarism and war plans. Every power had detailed mobilisation plans built around railway timetables. Germany’s Key term · 1905–1914 Schlieffen Plan Germany's war plan for fighting France and Russia at once — defeat France in about six weeks by sweeping through Belgium, then turn east. Why it matters It made mobilisation against Russia mean war with France and invasion of Belgium, which brought Britain in. Its failure at the Marne in 1914 led to trench stalemate. See in glossary → required it to attack France through Belgium as soon as Russia mobilised — turning any Russian–German crisis into a war in the West too.

Imperial and naval rivalry. Germany’s Key term · from 1897 Weltpolitik "World policy" — Germany's pursuit of colonies, naval power and global influence under Kaiser Wilhelm II. Why it matters It alarmed Britain, damaged relations with the other powers, and contributed to Germany's sense of encirclement. See in glossary → and its battle fleet pushed Britain towards France and Russia. Colonial crises over Morocco hardened attitudes.

Nationalism in the Balkans. Serbian nationalism threatened Austria-Hungary, a multinational empire with millions of South Slavs. After the Balkan Wars doubled Serbia’s size, many in Vienna saw war with Serbia as a matter of survival.

The July Crisis

Austria-Hungary decided to use the assassination to crush Serbia. It first sought German backing — and received the “blank cheque” of unconditional support. The ultimatum of 23 July was designed to be unacceptable; Serbia’s conciliatory reply was rejected anyway. Russia, protector of Serbia and unwilling to be humiliated as in 1908, mobilised. Germany’s war plan now dictated the next steps: war on Russia, then France, and the invasion of neutral Belgium.

Britain’s entry was not automatic. The German invasion of Belgium — whose neutrality Britain had guaranteed in 1839 — gave the British government its cause. German Chancellor Bethmann Hollweg reportedly complained that Britain was going to war over Quotation · 4 August 1914 Theobald von Bethmann Hollweg as reported by the British ambassador, Sir Edward Goschen Why it matters The phrase suggested that Germany treated international treaties as disposable — a gift to British propaganda about German militarism. .

The lamps are going out all over Europe; we shall not see them lit again in our life-time.

Sir Edward GreyBritish Foreign Secretary 3 August 1914 · Recalled in his memoirs, Twenty-Five Years (1925)
Why this quote matters

Grey's words capture the sense that this war would be different — and are often read as foresight of the catastrophe to come. Note that he recorded them in 1925, with hindsight of the war's cost.

Historians’ debate

The debate began with the peace treaty itself. Article 231 of the Treaty of Versailles — the Key term · 1919 War guilt clause Article 231 of the Treaty of Versailles, in which Germany accepted responsibility for the loss and damage caused by the war, as the legal basis for reparations. Why it matters Germans of all political views resented it as a national humiliation, and it fuelled the nationalist campaign against the Versailles settlement that Hitler exploited. See in glossary → — made Germany and its allies accept responsibility for the war.

German responsibility Fritz Fischer Griff nach der Weltmacht (Germany's Aims in the First World War) (1961)

Fischer argued that Germany’s leaders deliberately risked — even sought — a war to achieve European dominance, pointing to ambitious war aims drawn up in September 1914. His work caused a storm in West Germany.

Mobilisation plans A. J. P. Taylor War by Time-table (1969)

Taylor stressed how rigid railway mobilisation plans took decisions out of statesmen’s hands once mobilisation began.

Shared responsibility Christopher Clark The Sleepwalkers (2012)

Clark argued that responsibility was shared among all the powers, whose leaders — “sleepwalkers”, watchful but unseeing — made a series of decisions without grasping where they led. Critics say he underplays German and Austrian choices.

Test yourself

Why did the Schlieffen Plan make a wider war more likely? Reveal

It assumed a two-front war and required Germany to attack France quickly through Belgium as soon as Russia mobilised. Any crisis with Russia therefore became a war with France, and the invasion of Belgium brought in Britain.

What was the 'blank cheque', and why does it matter? Reveal

Germany’s promise of unconditional support to Austria-Hungary on 5–6 July 1914. It encouraged Vienna to take a hard line against Serbia, knowing Germany would back it even if Russia intervened.

How does Clark's interpretation differ from Fischer's? Reveal

Fischer placed the main responsibility on Germany’s leaders, who he argued pursued aggressive aims. Clark spread responsibility among all the powers, emphasising misjudgement and the complexity of the crisis rather than a deliberate drive to war.

Key terms

Anglo-German naval race 1898–1912

The competition between Britain and Germany to build battleships, intensified by Britain's launch of HMS Dreadnought in 1906.

Significance: It convinced Britain that Germany was a threat and pushed it towards France and Russia, although by 1912 Britain had clearly won the race.

Balkan Wars 1912–1913

Two wars in which the Balkan states first drove the Ottoman Empire out of most of Europe and then fought each other over the spoils.

Significance: Serbia doubled in size and confidence, convincing Austria-Hungary's leaders that Serbian nationalism threatened their empire's survival.

Black Hand 1911–1917

A secret Serbian nationalist society, led by army officers, that aimed to unite all Serbs — including those in Austria-Hungary — in a Greater Serbia.

Significance: It armed and trained the young Bosnian Serbs who assassinated Franz Ferdinand, giving Austria-Hungary its grounds to blame Serbia.

Blank cheque 5–6 July 1914

Germany's assurance to Austria-Hungary that it would support whatever action Vienna took against Serbia.

Significance: Historians who stress German responsibility see it as the key decision of the July Crisis, since it emboldened Austria-Hungary to risk war with Russia.

July Crisis July 1914

The month of diplomacy and decisions between the assassination in Sarajevo and the outbreak of general war.

Significance: It is where long-term tensions became war. Analysing each power's decisions during these weeks is essential to any argument about responsibility.

Schlieffen Plan 1905–1914

Germany's war plan for fighting France and Russia at once — defeat France in about six weeks by sweeping through Belgium, then turn east.

Significance: It made mobilisation against Russia mean war with France and invasion of Belgium, which brought Britain in. Its failure at the Marne in 1914 led to trench stalemate.

Triple Alliance 1882–1915

The defensive alliance of Germany, Austria-Hungary and Italy.

Significance: It bound Germany to Austria-Hungary's fate in the Balkans. Italy stayed neutral in 1914 and joined the other side in 1915, showing the limits of pre-war alliances.

Triple Entente 1907–1917

The informal alignment of France, Russia and Britain, built from the Franco-Russian alliance (1894), the Entente Cordiale (1904) and the Anglo-Russian Entente (1907).

Significance: Germany saw it as encirclement. Britain's commitments were looser than a formal alliance — which is why Belgium, not the Entente, decided its entry into the war.

War guilt clause 1919

Article 231 of the Treaty of Versailles, in which Germany accepted responsibility for the loss and damage caused by the war, as the legal basis for reparations.

Significance: Germans of all political views resented it as a national humiliation, and it fuelled the nationalist campaign against the Versailles settlement that Hitler exploited.

Weltpolitik from 1897

"World policy" — Germany's pursuit of colonies, naval power and global influence under Kaiser Wilhelm II.

Significance: It alarmed Britain, damaged relations with the other powers, and contributed to Germany's sense of encirclement.

Last updated 25 September 2026.

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