The Outbreak of War: Sarajevo and the July Crisis

By 1914 the Balkans were the most unstable region in Europe, so tense that they were nicknamed the "powder keg". Two forces collided there.

• Slav nationalism: Slav peoples, above all the Serbs, wanted to unite the Balkans into a single Slav state, free from foreign rule. Serbia was growing in confidence after victories in the Balkan Wars (1912–13).
• Austro-Hungarian control: Austria-Hungary was a multi-ethnic empire that ruled millions of Slavs. It saw an ambitious, independent Serbia as a deadly threat that could inspire its own Slav subjects to break away.

Behind Serbia stood Russia, which saw itself as the protector of the Slavs and was determined not to be humiliated again after backing down in the Bosnian crisis of 1908. The stage was set: any spark in the Balkans risked pulling in Austria-Hungary, then Russia, then their allies.

On 28 June 1914, Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, visited Sarajevo, the capital of Austrian-ruled Bosnia. He and his wife Sophie were shot dead by Gavrilo Princip, a 19-year-old Bosnian Serb.

Princip belonged to a nationalist movement supplied by the Black Hand, a secret Serbian group. Austria-Hungary believed — correctly — that the plot had been organised from inside Serbia.

The assassination was the trigger of the war, not its underlying cause. The alliances, rivalries and Balkan tensions were the explosives; Sarajevo was only the spark that lit them. A common exam error is to treat the murder as the cause of the war rather than the event that set deeper forces in motion.

Austria-Hungary now saw a golden opportunity: it could use the outrage to crush Serbia once and for all.

Austria-Hungary could not risk war with Serbia without knowing where Germany stood, because attacking Serbia risked bringing in Serbia's protector, Russia.

On 5–6 July 1914, Germany gave Austria-Hungary the so-called "blank cheque" — a promise of full, unconditional support whatever Austria decided to do. Kaiser Wilhelm II and his government encouraged Austria to act quickly and firmly.

The consequences were enormous:

• It made Austria-Hungary confident enough to risk war, even knowing Russia might respond.
• It showed Germany was willing to back a war rather than hold its ally back.
• It is one reason many historians place significant responsibility for the escalation on Germany.

Exam link: the blank cheque is a strong point when explaining how a local crisis became a general war. It shows a deliberate choice, not just an accident, driving events forward.

The five weeks between the assassination and the outbreak of war are known as the July Crisis. Once the mobilisations began, events moved faster than the leaders could control.

Austria's ultimatum of 23 July was deliberately harsh, designed to be rejected. Serbia accepted nearly all of it, but Austria declared war anyway on 28 July 1914.

Why did a war between Austria-Hungary and Serbia pull in the whole continent so quickly? The answer is the alliance system combined with rigid mobilisation timetables.

• Russia mobilised (30 July) to protect Serbia. Its plans were slow, so it began early — but mobilising against Austria meant mobilising near Germany too.
• Germany saw Russian mobilisation as a threat it had to answer at once. Its war plan (the Schlieffen Plan) depended on striking France fast, before Russia was ready, so any delay was dangerous.
• Germany declared war on Russia (1 August) and then France (3 August).

Mobilisation plans acted like a trap. Once one power began, its rivals felt they had to start too, or lose the advantage. Timetables built for speed left almost no room for diplomacy. This is a key reason the crisis escalated in days, not months.

Leaders were also handicapped: the French President and Prime Minister were literally at sea for much of late July, out of easy contact.

Germany's Schlieffen Plan required its armies to sweep through neutral Belgium to attack France. On 4 August 1914, German troops crossed the Belgian border.

This drew in Britain. Britain had guaranteed Belgian neutrality under the Treaty of London (1839), and it was unwilling to see Germany dominate the Channel coast opposite England. On 4 August 1914, Britain declared war on Germany.

Country	Enters the war	Main reason
Austria-Hungary	28 July	To crush Serbia after the assassination
Russia	Mobilised 30 July	To protect Serbia and Slav interests
Germany	1 & 3 August	Alliance with Austria; two-front war fears
France	3 August	Franco-Russian Alliance; attacked by Germany
Britain	4 August	Defence of Belgian neutrality; balance of power

Within a single week, a murder in the Balkans had become a war involving every great power in Europe.

1. Calling the assassination "the cause" of the war

The murder of Franz Ferdinand was the trigger. The causes were long-term: alliances, rivalry, the naval race and Balkan tension. Separate the spark from the explosives.

2. Getting the July dates in the wrong order

Learn the sequence: assassination (28 June) → blank cheque (5–6 July) → ultimatum (23 July) → Austria declares war (28 July) → mobilisations → Belgium and Britain (4 August). Muddled chronology weakens a "write an account" answer.

3. Forgetting why Britain joined

Britain did not enter for Serbia. It entered because Germany invaded neutral Belgium and threatened the balance of power. State this reason precisely.

4. Ignoring the role of mobilisation

The rigid timetables are what made escalation so fast. A strong answer explains that once Russia and Germany mobilised, diplomacy ran out of time — do not leave this out.

5. Describing events without explaining escalation

For a "write an account" question, do not just list what happened. Show how each step increased tension and pulled in another power, so a local dispute became a general war.