What Were the Main Causes of World War One?

What Were the Main Causes of World War One?

It would appear that the very root of the cause of WWI was the assassination of the heir to the Austrian-Hungarian throne. To me, this is an incredibly odd reason to start a world war. Was the war as pointless as it seems?


If you look at it in the context of European wars of the past few centuries, it isn't totally out of line. Europe had seen a good many wars, some with even less justification. It also grew quickly once the Great Powers got involved. Austria-Hungary decided to attack Serbia, Russia decided to support Serbia, and Germany decided to support Austria-Hungary. None of these acts were particularly odd by past criteria, but such rapid expansion was unusual. While many European powers could wind up in a war, they generally did so more slowly, with more time for diplomacy.

Germany's war plan didn't help. In event of war with Russia, the German Army would form up on Germany's western border, invade Belgium, and march on Paris, making it impossible to contain the war once Germany decided to support Austria-Hungary against Russia.

Once the war had started, the great increase in army size precluded maneuver, and the unexpected resilience of industrial economies made attrition a long, slow, process. Moreover, each belligerent was suffering greatly in the war, and it rapidly became politically impossible for each side to accept a peace that wasn't some sort of victory over the other.


Causes of the First World War

There are many reasons why Europe was on the brink of war in 1914. Militarism, the Alliance System, Imperialism and Nationalism combined to make the build up of arms in Europe inevitable. The causes of the First World War are complex. Historians have formed various views on the precise nature of the causes. Historiography of the outbreak of the Great War has seen each of the ‘Main’ areas emphasised as the primary cause by different historians over the years. This ranges from German aggression, as seen in the war guilt clauses, to explanations looking at the financial or domestic political reasons for the outbreak of war.

For historiography of the causes of the Great War see this unit, aimed at A Level and above. For a broader overview of the reasons why the war broke out, see below. Our main section on the First World War can be found here.


European Expansionism

In the 1900s, several European nations had empires across the globe, where they had control over vast swaths of lands. Prior to World War I, the British and French Empires were the world&rsquos most powerful, colonizing regions like India, modern-day Vietnam and West and North Africa. The expansion of European nations as empires (also known as imperialism) can be seen as a key cause of World War I, because as countries like Britain and France expanded their empires, it resulted in increased tensions among European countries. The tensions were a result of many colonies often being acquired through coercion. Then, once a nation had been conquered, it was governed by the imperial nation: many of these colonial nations were exploited by their mother countries, and dissatisfaction and resentment was commonplace. As British and French expansionism continued, tensions rose between opposing empires, including Germany, Austria-Hungary and the Ottoman Empire, leading to the creation of the Allied Powers (Britain and France) and Central Powers (Germany, Austria-Hungary and the Ottoman Empire) during World War I.


Causes of WW1: Nationalism

Nationalism means being a strong supporter of the rights and interests of one’s country. The Congress of Vienna, held after Napoleon’s exile to Elba, aimed to sort out problems in Europe. Delegates from Britain, Austria, Prussia, and Russia (the winning allies) decided upon a new Europe that left both Germany and Italy as divided states. Strong nationalist elements led to the reunification of Italy in 1861 and Germany in 1871. The settlement at the end of the Franco-Prussian war left France angry at the loss of Alsace-Lorraine to Germany and keen to regain their lost territory. Large areas of both Austria-Hungary and Serbia were home to differing nationalist groups, all of whom wanted freedom from the states in which they lived.


Pre World War One - The failure of the Schlieffen Plan

Germany was keen to invade France before going on to fight Russia. Germany had a strategy to invade France, known as the Schlieffen Plan . This plan had been in place since 1897. The Germans thought that Russia would be the real danger and that they could easily defeat France within weeks.

This plan had a number of flaws:

  • Germany needed to go through Belgium, a neutral country, to get to France. Britain warned Germany not to do this. Germany carried on with the Schlieffen Plan. The small Belgian army fought bravely and slowed down the German advance.
  • A Britain has signed the Treaty of London in 1839 promising to protect Belgium. As a result Britain sent the British Expeditionary Force to Belgium slowing the Germans down at the Battle of Mons.
  • On the 19th August Russia invaded Germany much quicker than the Germans had expected. This forced Germany to move 100,000 troops back to support which weakened the German advance.
  • The Battle of Marne (Germans advance on Paris) saw the British and French armies push the Germans back to the river Aisne where they began to dig trenches.

This video looks at the Schlieffen Plan

Cases of World War One

British people were keen to join up and fight in the First World War. Nobody imagined that it would last for four years and cost the lives of 3 million allied soldiers.

Britain had an alliance with France and Russia, called the Triple Entente (An alliance formed between the Britain, France, and Russia in 1907, which would lead to their partnership in the First World War).

Germany had a similar agreement with the Austro-Hungarian Empire and Italy. This was known as the Triple Alliance.

The Austro-Hungarian Archduke Franz Ferdinand was assassinated by a Serb called Gavrilo Princip, in the Bosnian capital Sarajevo on 28 June 1914. Angered by this, the Austro-Hungarian Empire declared war on Serbia.

Russia agreed to help Serbia. Germany agreed to help the Austro-Hungarian Empire by declaring war on Russia on 31 July 1914 and then on France.


Did Franz Ferdinand’s Assassination Cause World War I?

The causes of World War I, also known as the Great War, have been debated since it ended. Officially, Germany shouldered much of the blame for the conflict, which caused four years of unprecedented slaughter. But a series of complicated factors caused the war, including a brutal assassination that propelled Europe into the greatest conflict the continent had ever known.

The murder of Archduke Franz Ferdinand outraged Austria-Hungary.
In June 1914, Austrian Archduke Franz Ferdinand and his wife Sophie traveled to Bosnia—which had been annexed by Austria-Hungary𠅏or a state visit.

On June 28, the couple went to the capital city of Sarajevo to inspect imperial troops stationed there. As they headed toward their destination, they narrowly escaped death when Serbian terrorists threw a bomb at their open-topped car.

Franz Ferdinand, archduke of Austria, and his wife Sophie riding in an open carriage at Sarajevo shortly before their assassination. (Credit: Henry Guttmann/Getty Images)

Their luck ran out later that day, however, when their driver inadvertently drove them past 19-year-old Serbian nationalist Gavrilo Princip who shot and killed Franz Ferdinand and his wife at point-blank range. Austria-Hungary was furious and, with Germany’s support, declared war on Serbia on July 28.

Within days, Germany declared war on Russia—Serbia’s ally𠅊nd invaded France via Belgium, which then caused Britain to declare war on Germany.

Limited industrial resources fueled imperialist expansion.
A state’s desire to expand its empire was nothing new in European history, but by the early 20th century the Industrial Revolution was in full force.

New industrial and manufacturing technologies created the need to dominate new territories and their natural resources, including oil, rubber, coal, iron and other raw materials.

With the British Empire extending to five continents and France controlling many the African colonies, Germany wanted a larger slice of the territorial pie. As countries vied for position, tensions rose, and they formed alliances to position themselves for European dominance.

The rise of nationalism undermined diplomacy.
During the 19th century, rising nationalism swept through Europe. As people took more pride in country and culture, their desire to rid themselves of imperial rule increased. In some cases, however, imperialism fed nationalism as some groups claimed superiority over others.

This widespread nationalism is thought to be a general cause of World War I. For instance, after Germany dominated France in the Franco-Prussian War of 1870-71, France lost money and land to Germany, which then fueled French nationalism and a desire for revenge.

Nationalism played a specific role in World War I when Archduke Ferdinand and his wife were assassinated by Princip, a member of a Serbian nationalist terrorist group fighting against Austria-Hungary’s rule over Bosnia.

Kings William I, Franz Josef and Umberto I, on the occasion of the signing of the Triple Alliance, Treaty between the German Empire, Austria-Hungary and the Kingdom of Italy, 1882. (Credit: DeAgostini/Getty Images)

Entangled alliances created two competing groups.
In 1879, Germany and Austria-Hungary allied against Russia. In 1882, Italy joined their alliance (The Triple Alliance) and Russia responded in 1894 by allying with France.

In 1907, Great Britain, Russia and France formed the Triple Entente to protect themselves against Germany’s growing threat. Soon, Europe was divided into two groups: The Central Powers of Germany, Austria-Hungary and Italy and the Allies, which included Russia, France and Britain.

As war was declared, the allied countries emboldened each other to enter the fray and defend their treaties, although not every coalition was set in stone—Italy later changed sides. By the end of August 1914, the so-called 𠇎ntangled alliances” had caused what should have been a regional conflict to expand to all of Europe’s powerful states.

Militarism sparked an arms race.
In the early 1900s, many European countries increased their military might and were ready and willing put it to use. Most of the European powers had a military draft system and were in an arms race, methodically increasing their war chests and fine-tuning their defense strategies.

Between 1910 and 1914, France, Russia, Britain and Germany significantly increased their defense budgets. But Germany was by far the most militaristic country in Europe at the time. By July 1914, it had increased its military budget by a massive 79 percent.

Germany was also in an unofficial war with Britain for naval superiority. They doubled their naval battle fleet as Britain’s Royal Navy produced the first Dreadnought battleship which could outgun and outrun any other battleship in existence. Not to be outdone, Germany built its own fleet of Dreadnoughts.

By the start of World War I, the European powers were not just prepared for war, they expected it and some even counted on it to increase their world standing.

Although the assassination of Archduke Ferdinand was the spark that caused Austria-Hungary to strike the first blow, all the European powers quickly fell in line to defend their alliances, preserve or expand their empires and display their military might and patriotism.


Pre-WWII Conquests

Italian invasion of Albania

Before WWII had officially begun, the powers that would merge to form the Axis had already launched campaigns of conquest. Shortly after Hitler came to power, he managed to seize control of Austria and part of what was then Czechoslovakia without any major combat operation. Italy had already conquered both Ethiopia and Albania, and Japan was expanding its imperial realm decades before WWII began, conquering the Korean peninsula, Taiwan, and the southern half of the Far East Soviet island of Sakhalin. In 1931, Japan began its attempt to conquer China by invading Manchuria. The fact that the Axis powers were able to expand their territory with little to no resistance from rest of the international community only emboldened them to make further conquests.


The Main Alliances

The alliances formed before the war changed over time and over the course of the conflict. Here are the major ones:

Dual Alliance (1879): An agreement between Austria-Hungary and Germany to protect themselves from war with Russia.

The Triple Alliance (1882): Between Austria-Hungary, Germany and Italy over territory in the Balkans.

Franco-Russian Alliance (1891): Changed and modified over time, the alliance was never satisfying to either France or Russia. It was intended to counter-balance the Triple Alliance.

The Entente Cordiale (1904): An alliance between Great Britain and France, meant to balance any alliance Germany made with its allies.

Anglo-Russian Entente (1907): Between Great Britain and Russia, it settled territorial claims in Asia.

Triple Entente (1907): Between Britain, France and Russia, these nations became the Allies when war began seven years later.


Alliances as a cause of World War I

Though their significance is often misunderstood or exaggerated, alliances are one of the best-known causes of World War I. While alliances did not force nations to war in 1914, they nevertheless drew them into confrontation and conflict with their neighbours.

What is an alliance?

An alliance is a political, military or economic agreement, negotiated and signed by two or more nations. Military alliances usually contain promises that in the event of war or aggression, signatory nations will support their allies.

The terms of this support are outlined in the alliance document. They can range from financial or logistic backing, like the supply of materials or weapons, to military mobilisation and a declaration of war against the aggressor.

Alliances may also contain economic elements, such as trade agreements, investment or loans.

Origins of the alliance system

In many respects, the pre-war alliance network as a byproduct of European geopolitics. Europe had long been a melting pot of ethnic and territorial rivalries, political intrigues and paranoia.

France and England were ancient antagonists whose rivalry erupted into open warfare several times between the 14th and early 19th centuries. Relations between the French and Germans were also troubled, while France and Russia also had their differences.

Alliances provided European states with a measure of protection. They served as a means of guarding or advancing national interests while acting as a deterrent to war. They were particularly important for Europe’s smaller or less powerful states.

Anti-Napoleonic alliances

During the 1700s, kings and princes regularly formed or re-formed alliances, usually to protect their interests or to isolate rivals. Many of these alliances and alliance blocs were short-lived. Some collapsed when new leaders emerged others were nullified or replaced by new alliances.

The rise of French dictator Napoleon Bonaparte in the early 1800s ushered in a brief period of ‘super alliances’. European nations allied themselves either in support of Bonaparte or to defeat him. Between 1797 and 1815, European leaders formed seven anti-Napoleonic coalitions. At various times these coalitions included Britain, Russia, Holland, Austria, Prussia, Sweden, Spain and Portugal.

After Napoleon’s defeat at Waterloo in 1815, European leaders worked to restore normality and stability to the continent. The Congress of Vienna (1815) established an informal system of diplomacy, defined national boundaries and sought to prevent wars and revolutions. The congress system worked for a time but started to weaken in the mid-1800s.

The late 19th century

Imperial interests, changes in government, a series of revolutions (1848) and rising nationalist movements in Germany, Italy and elsewhere saw European rivalries and tensions increase again in the mid-1800s.

During the late 19th century, European leaders continued to form, annul and restructure alliances on a regular basis. The alliance system during this period is often attributed to German chancellor Otto von Bismarck and his attitude of realpolitik.

Some individual agreements signed during this period include:

The Treaty of London (1839)

Though not a formal alliance, this multi-lateral treaty acknowledged the existence of Belgium as an independent and neutral state. Several of Europe’s great powers, including Great Britain and Prussia, were signatories to this treaty.

Belgium had earned statehood in the 1830s after separating from southern Holland. The Treaty of London was still in effect in 1914, so when German troops invaded Belgium in August 1914, the British considered it a violation of the treaty.

The Three Emperors’ League (1873)

The Three Emperors’ League was a three-way alliance between the ruling monarchs of Germany, Austria-Hungary and Russia. It was engineered and dominated by the Prussian statesman Otto von Bismarck, who saw it as a means of securing the balance of power in Europe.

Disorder in the Balkans undermined Russia’s commitment to the league, which collapsed in 1878. The Three Emperors’ League, without Russia, came to form the basis of the Triple Alliance.

The Dual Alliance (1879)

The Dual Alliance was a binding military alliance between Germany and Austria-Hungary. It required each signatory to support the other if one was attacked by Russia. It was signed after the collapse of the Three Emperors’ League and during a period of Austro-Russian tension in the Balkans.

The Dual Alliance was welcomed by nationalists in Germany, who believed that German-speaking Austria should be absorbed into greater Germany.

The Triple Alliance (1882)

This complex three-way alliance between Germany, Austria-Hungary and Italy was motivated chiefly by anti-French and anti-Russian suspicions and sentiment.

Each of the three signatories to the Triple Alliance was required to provide military support to the others, if one was attacked by two other powers – or if Germany and Italy were attacked by France.

Italy, a newly formed nation that was weak militarily, was viewed as a minor partner in this alliance.

The Franco-Russian Alliance (1894)

This military alliance between France and Russia restored cordial relations between the two imperial powers. It was, in effect, a response to the Triple Alliance, which had isolated France.

The signing of the Franco-Russian Alliance was an unexpected development that thwarted German plans for mainland Europe. The alliance angered Berlin and triggered a more aggressive shift in its foreign policy.

The Franco-Russian Alliance also provided economic benefits to both signatory nations. It gave Russia access to French loans and provided French capitalists with access to Russian mining, industry and raw materials. This was an important factor in the industrialisation of Russia over the next two decades.

The Entente Cordiale (1904)

Meaning ‘friendly agreement’, the Entente Cordiale was a series of negotiations and agreements between Britain and France, finalised in 1904.

The Entente ended a century of hostility between the two cross-channel neighbours. It also resolved some colonial disagreements and other minor but lingering disputes.

The Entente was not a military alliance since neither signatory was obliged to provide military support for the other. Nevertheless, it was seen as the first step towards an Anglo-French military alliance.

The Anglo-Russian Entente (1907)

This agreement between Britain and Russia eased tensions and restored good relations between London and Saint Petersburg.

Britain and Russia had spent much of the 19th century as antagonists. They went to war in the Crimea (1853-56) and later twice neared the brink of war.

The Anglo-Russian Entente resolved several points of disagreement, including the status of colonial possessions in the Middle East and Asia. It did not involve any military commitment or support.

The Triple Entente (1907)

This treaty consolidated the Entente Cordiale and the Anglo-Russian Entente into a three-way agreement between Britain, France and Russia.

Again, The Triple Entente was not a military alliance – but the three Ententes of 1904-7 were important because they marked the end of British neutrality and isolationism.

A Venn diagram depicting the network of alliances in 19th and 20th century Europe

Secrecy and hidden clauses

Unlike most multilateral agreements today, these alliances and ententes were formulated behind closed doors and only revealed to the public after signing.

Some governments even conducted negotiations without informing their other alliance partners. The German chancellor Bismarck, for example, initiated alliance negotiations with Russia in 1887 without informing Germany’s major ally, Austria-Hungary.

Some alliances also contained ‘secret clauses’ that were not publicly announced or placed on record. Several of these secret clauses only became known to the public after the end of World War I. The secretive nature of alliances only heightened suspicion and continental tensions.

A depiction of the two alliance blocs, each pulling against the other

Secret clauses

An additional factor in the outbreak of war were changes to European alliances in the years prior to 1914. A clause inserted into the Dual Alliance in 1910, for example, required Germany to directly intervene if Austro-Hungary was ever attacked by Russia.

These modifications were ostensibly small but they further strengthened and militarised alliances. It is debatable whether these changes increased the chances of war or simply reflected the rising tensions of the period.

The impact of the alliance system as a cause of war is often overstated. Alliances did not, as is often suggested, make war inevitable. These pacts and treaties did not disempower sovereign governments or drag nations into war against their own will.

The authority and final decision to mobilise or declare war still rested with national leaders. It was their moral commitment to these alliances that was the telling factor. As historian Hew Strachan put it, the real problem was that by 1914, “nobody was prepared to fight wholeheartedly for peace as an end in itself”.

A historian’s view:
“Models of the war’s causality have often expressed contemporary international relations. During the Cold War and the division of the world into two, there was a tendency to view international relations before 1914 as bipolar, and divided between two rigidly separated and rival blocs in which power, prestige and security were key determinants and in which emphasis was placed on the alliance system in the war’s causes… Analysis turned on how far war was accidental (or ‘system generated’) and how far it was willed by governments.”
John Horne

1. The alliance system was a network of treaties, agreements and ententes that were negotiated and signed prior to 1914.

2. National tensions and rivalries have made alliances a common feature of European politics, however, the alliance system became particularly extensive in the late 1800s.

3. Many of these alliances were negotiated in secret or contained secret clauses, adding to the suspicion and tension that existed in pre-war Europe.

4. The Triple Alliance (Germany, Austria-Hungary and Italy) formed the basis of the Central Powers, the dominant alliance bloc in central Europe.

5. Britain, France and Russia overcame their historical conflicts and tensions to form a three-way entente in the early 1900s.