Causes and outbreak of World War One


Rising tension and alliances between countries

The outbreak of the First World War was the result of growing tensions between countries and the expansion of their borders and industry, along with lingering animosity in the wake of several wars at the end of the 19th Century, such as the Franco-Prussian War between France and Germany.

Numerous treaties and alliances, formed as pre-emptive measures within the years leading up to the war, also contributed to the eventual conflict, the most prominent of which being:

  • The Triple Alliance (formed in 1882): Germany, Austria-Hungary and Italy
  • The Triple Entente (formed during 1904-1907): Britain, France and Russia
Germany’s growth

Germany’s previous victories, specifically during the Austro-Prussian War (1866) and the Franco-Prussian War (1870-71) had resulted in its territories and industry growing significantly. Its military had also become a force to be reckoned with, due to its revolutionary system of compulsory conscription and training regimes, resulting in both active and reserve units, ready for service in the event of war. Its modernised weaponry and tactics also contributed to its overall threat.

The threat posed by Germany’s increasing expansion across Europe, and the aggressive reign of Kaiser Wilhelm II from 1871, resulted in mounting concern from its neighbours, particularly France and Russia, who would pledge to support each other in the event of war.

Gavrilo Princip assassinates Franz Ferdinand
Gavrilo Princip assassinates Franz Ferdinand
The assassination of Archduke Franz Ferdinand

The annexation of the previously disputed zone of Bosnia in 1908, by Austria-Hungary, tensions rose between Austria-Hungary and Serbia, due to Serbia’s recognition as an independent country in 1878, and the population of Bosnia consisting mainly of Serbians. Their desire for independence from Austria-Hungary would eventually give rise to the nationalist movement Narodna Obrana (National Defence) and its terrorist branch, The Black Hand.

On 28 June 1914, The Black Hand would attempt to assassinate Archduke Franz Ferdinand, heir to the throne of Austria-Hungary, during his visit to the Bosnian capital of Sarajevo to oversee army manoeuvres, on the day of the Vivdovan national festival. Ultimately, after several failed attempts, including an attempt to kill the Archduke with a bomb thrown at his car, Ferdinand and his wife, Sophie, were shot dead by Black Hand member Gavirlo Princip. Following the confession of the assassins after their arrest, in regards to their Serbian origin, Austria-Hungary would, with Germany’s support, declare war upon Serbia on 28 July 1914.

Declarations of war

The assassination of Archduke Franz Ferdinand, and Austria-Hungary’s declaration of war, would spark the conflict of the First World War:

  • Russia, having previously pledged to defend Serbia’s independence, mobilised its military forces on 30 July 1914, to combat Austria-Hungary.
  • In retaliation, in accordance with its support of Austria-Hungary, and fearing a threat towards its own empire from two fronts, Germany would prepare its own forces on 30 July 1914, intending to attack both Russia and France. Germany would then formally declare war on Russia on 1 August 1914. This, in turn, led to France mobilising its own forces, due to its previous alliance with Russia, and to Germany declaring war on France on 3 August 1914. By 5 August 1914, Austria-Hungary had also declared war on Russia.
  • Britain, having previously been reluctant to go to war, would ultimately declare war on Germany on 4 August 1914, its motive being the protection of Belgium’s neutrality. Following its demand for safe passage through Belgian territory on 2 August 1914, which had been refused the following day, Germany had begun an aggressive advance through Belgium and Luxembourg in order to attack France.