The Origins and Outbreak of World War I

Public Domain

How did World War One break out? Professor David Stevenson closely examines the three stages that led to war being declared between Austria-Hungary, Serbia, Germany, Russia, France, and Britain.

By Dr. David Stevenson / 01.29.2014
Stevenson Professor of International History
The London School of Economics and Political Science

In July-August 1914 an international crisis culminated in the outbreak of the First World War. The crisis had three phases. In the first, one of the six European Great Powers, Austria-Hungary, launched a war against Serbia. In the second, this war escalated into a Continent-wide conflict involving Germany, Russia, and France. In the third, the conflict spread into Western Europe as Germany invaded Luxemburg and Belgium, and Britain intervened. The sixth Great Power, Italy, remained neutral.

Phase one: Austria-Hungary declares war against Serbia

In its later stages the crisis ran at breakneck speed, but at first it moved slowly. It began with the assassinations on 28 June of the Archduke Franz Ferdinand and his wife, Sophie, at Sarajevo by Gavrilo Princip. Franz Ferdinand was heir to the Austro-Hungarian throne. He fell victim to what would now be called state-sponsored terrorism. Princip was an ethnic Serb from Bosnia, which Austria-Hungary had annexed in 1908. He belonged to a revolutionary nationalist group that wanted to liberate the South Slav peoples (Serbs, Croats, and Slovenes) from foreign rule and unite them in a new state of Yugoslavia. The conspirators had received their weapons from Serbian military intelligence and been trained in Belgrade, although the Serbian civilian government had not been involved. It was therefore unsurprising that Austria-Hungary made drastic demands on Serbia in an ultimatum delivered on 23 July. But the Austro-Hungarian leaders wanted to use the assassinations to provoke a war, and to a British radical such as David Lloyd George their conduct amounted to bullying. When Serbia failed to accept all of the demands, Austria-Hungary declared war on 28 July.

A flyer by Franz Joseph, M.D.

Phase two: the conflict widens to Germany, Russia, and France

Austria-Hungary’s leaders ruled a multi-national empire. They felt that Serbian-backed separatism threatened its survival. Already by 1913 they had decided that only force could solve the problem. But they knew a war against Serbia was almost certain to escalate, and before sending the ultimatum they consulted their ally, Germany, whose leaders urged Austria-Hungary to use force and promised backing if Russia intervened (the secret ‘Potsdam blank cheque’, 5-6 July). The Germans’ motives have been intensively debated. From their perspective, Austria-Hungary was their one reliable Great-Power ally, and enemies ringed them. France and Russia had allied in 1891-94, and since 1904 Britain had co-operated with them. Germany had conducted a battleship-building race against Britain and an army race against France and Russia, and since 1905 the two blocs had clashed repeatedly over Morocco and the Balkans. The German leaders were readier to risk war because they believed the current military balance favoured them but would soon deteriorate. But if Germany threw down a challenge, Russia was quick to respond. Once Austria-Hungary sent the ultimatum Russia began military preparations, and after war was declared on Serbia, Russia ordered ‘general mobilisation’ (31 July), placing its forces on a war footing. Russia’s leaders were willing to accept a European conflict rather than abandon Serbia, partly because of Slav solidarity but more to protect their own interests in the Balkans and because they saw Germany as a danger. They had recently strengthened their army, and they correctly expected France to support them.

Satirical map of Europe drawn by German graphic artist Walter Trier in 1914, showing Germany and Austria-Hungary as aggressors. / British Library, Public Domain

Phase three: Germany invades Luxemburg and Belgium, Britain intervenes

Brochure summarising the history of Alsace-Lorraine which by 1914 had been part of the German Empire for 50 years. / British Library, Public Domain

Germany and France had been at odds since the Franco-Prussian War of 1870-71, after which Germany had annexed the French provinces of Alsace-Lorraine. The French remembered the loss, although they would not have started a war over it. Germany’s strategy for a war against France and Russia envisaged first defeating France quickly, outflanking France’s border fortresses by invading via Luxemburg and Belgium. Once Russia mobilized (which the Germans feared would undermine their war plan) the Germans declared war on both Russia and France (1 and 3 August) and demanded that Belgium allow them to cross its territory. Britain, Germany, and France had all committed themselves to respect Belgian independence by the 1839 Treaty of London, and the issue swung the doubters in the British Cabinet. As Germany failed to comply with a demand to respect Belgium, on 4 August Britain declared war.

Booklet published in June 1916 by Margaret L. Blaise (née Jones, 1878-1935), pioneer of the Esperanto movement in Britain. / British Library, Public Domain

In 1914 a Balkan crisis coincided with high tension between Europe’s opposing power blocs. For decades the continent had enjoyed relative peace, and many had believed that war was becoming obsolete: some called for a common language such as Esperanto. Now, however, anti-war opposition collapsed, because events moved too quickly and the full facts of the crisis remained hidden, and because each government could present the conflict as a defensive struggle forced on it by the enemy. Partly for this reason, at least until 1917 pro-war consensus generally remained solid.

Originally published by the British Library under a Creative Commons Attribution 4.0 International license.