The First World War began in 1914 after a crisis that followed an assassination in Sarajevo. Long-term tensions between the European powers helped make a wider war more likely, and historians weigh the importance of each differently. This page gives the dated facts and shows how to keep long-term causes, the trigger and interpretations apart.
It belongs to core option A study pathways. Your own syllabus year decides the detail you need, so check the Cambridge page.
There is also a separate pathway in the First World War depth study if it is your selected option. For causal wording, see qualified causal language.
What were the long-term tensions?
These are facts you can check in standard reference works.
- 1882: the Triple Alliance linked Germany, Austria-Hungary and Italy.
- 1894: France and Russia agreed an alliance.
- 1904 and 1907: Britain reached understandings with France (the Entente Cordiale) and with Russia, forming the Triple Entente with them.
- 1905 and 1911: two crises over Morocco involving France and Germany.
- 1906 onwards: a naval building race between Britain and Germany after the launch of HMS Dreadnought.
- 1908: Austria-Hungary annexed Bosnia, increasing tension with Serbia.
- 1912 to 1913: the Balkan Wars changed the balance of power in the region.
What happened in the 1914 crisis?
- 28 June: Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, was assassinated in Sarajevo.
- 23 July: Austria-Hungary sent an ultimatum to Serbia.
- 28 July: Austria-Hungary declared war on Serbia.
- 1 August: Germany declared war on Russia.
- 3 August: Germany declared war on France.
- 4 August: Germany invaded Belgium, and Britain declared war on Germany.
Worked example: sort and link
Question: How far was the alliance system a cause of the war?
Step 1, sort. The alliances are a long-term factor. The assassination is the trigger. The decisions between 23 July and 4 August are the chain of events linking the two.
Step 2, link. Because Austria-Hungary was tied to Germany, and Serbia was linked to Russia, a local dispute became a wider one. That is a reasoned link, so use the wording “helped to widen”.
Step 3, add other factors. The naval race, the Moroccan crises and the Balkan tensions also built mistrust. The alliances were therefore one factor among several.
Step 4, judgement. “The alliance system helped to widen a regional crisis into a continental war, but it does not explain by itself why Austria-Hungary and Germany chose to act as they did in July, so it was an important factor rather than the only one.”
The paragraph does not blame any state. It weighs how far one factor explains the outcome.
The mistake to watch for
A student writes: “The alliances caused the war, so the assassination did not matter.”
This ignores the trigger. Without the assassination, the specific crisis of July 1914 would not have occurred when it did. The correction is to give each part its role: “The alliances made a wider war more likely, and the assassination was the trigger that started the chain of decisions.”
Check yourself
1. Is the assassination at Sarajevo a long-term cause or a trigger?
Show answer
A trigger. It was an immediate event on 28 June 1914 that began the July crisis.
2. Name the two groups of powers in the alliance system by 1907.
Show answer
The Triple Alliance (Germany, Austria-Hungary, Italy) and the Triple Entente (Britain, France, Russia).
3. Is “Germany was mainly to blame” a fact or an interpretation?
Show answer
An interpretation. It is a judgement about responsibility, which historians reach by weighing evidence differently.
Where this leads next
Apply the sorting method to the earlier cases in the American Civil War, then test yourself with the integrated practice set.
Questions about responsibility are easier to answer fairly with practice on your own paragraphs, and a teacher in online one-to-one History tuition can review them with you.