Countdown to war: The events that triggered WW1

Archduke Franz Ferdinand and his wife pictured shortly before they were assassinated. Credit: PA Wire

The assassination of Archduke Franz Ferdinand is widely believed to have triggered the events leading to the First World War, prompting a web of treaties and alliances that led to war on an unprecedented scale.

Here is the countdown to the Great War:

  • June 28, 1914

Archduke Franz Ferdinand was heir to the Austro-Hungarian Empire when he was assassinated. Credit: DPA/DPA/Press Association Images

Archduke Franz Ferdinand, heir to the throne of the Austro-Hungarian Empire, and his wife Sophie are shot dead in Sarajevo.

The assassinations are the work of Serbian nationalists who want to bring the empire's Slav territory into a greater Serbia.

  • July 23, 1914

Austro-Hungarian infantry practice shooting at the border to Serbia in 1914. Credit: dpa/DPA/Press Association Images

Austria-Hungary's reaction to the killings comes three weeks later, when it sends an ultimatum to Serbia.

It gives Serbia 48 hours to comply with its strict terms.

  • July 24, 1914

British Foreign Secretary Sir Edward Grey called for country's to act together to ensure peace. Credit: Tophams/Topham Picturepoint/Press Association Images

Germany declares its support for Austria.

British Foreign Secretary Sir Edward Grey asks that Germany, France, Italy and Britain should "act together for the sake of peace simultaneously".

  • July 25, 1914

Extra issues being handed out of newspapers announcing King Peter I's order to mobilise Serbian troops. Credit: DPA/DPA/Press Association Images

Serbia orders its troops to mobilise while Russia, bound by treaty to Serbia, arranges for soldiers to be stationed on the Austrian frontier.

  • July 28, 1914

Austro-Hungarian troops seen in a built out position in the southern part of Russia. Credit: DPA/DPA/Press Association Images

Austria-Hungary declares war on Serbia.

  • July 29, 1914

A protest against Austria-Hungary in front of Belgrade's national theatre takes place in July 1914. Credit: DPA/DPA/Press Association Images

Britain warns Germany that it cannot remain neutral in the conflict.

On the same day, Austria bombards the Serbian capital of Belgrade.

  • July 31, 1914

People in Germany grab newspapers as the mobilisation of the country's troops is announced. Credit: DPA/DPA/Press Association Images

Russian general mobilisation is ordered. Austria also mobilises its troops

Germany prepares for war and sends an ultimatum to Russia demanding that military preparations are stopped within 12 hours.

Britain asks France and Germany to declare their support for the ongoing neutrality of Belgium - but while France agrees, Germany does not respond.

Germany asks France whether it would stay neutral in case of a war between Germany and Russia.

  • August 1, 1914

A boy carries his father's bag and gun to the train station in Germany. Credit: DPA/DPA/Press Association Images

Germany declares war on Russia.

French mobilisation is also ordered.

  • August 3, 1914

The first German troops cross the French border in August 1914. Credit: DPA/DPA/Press Association Images

Germany declares war on France.

Britain gives the order for its troops to mobilise.

Germany tells Belgium that it will "treat her as an enemy" if the country does not allow free passage of German troops across Belgium land to fight the French.

Britain gives Austria-Hungary an ultimatum to stand down from hostilities.

  • August 4, 1914

British weaponry is put to the test during the Great War. Credit: Topham/Topham Picturepoint/Press Association Images

Britain, having failed to receive notice from Germany assuring the neutrality of Belgium, and citing a "moral obligation" to defend France and Belgium, declares war on Germany.