The arms race
From 1900 onwards, all the Great Powers increased the size of their armed forces
Britain and Germany were also involved in a naval arms race. As an island, Britain had always had a large navy. The German Kaiser wanted to build up the German navy. In 1906, the British launched a new type of battleship. The German Kaiser wanted to keep up so thought he needed to do the same, and so a naval arms race began.
Immediate events leading to the outbreak of war
28 June: (Austrian Archduke) Franz Ferdinand and his wife were shot in Sarajevo
23 July: Austrian Government delivers an ultimatum to the Serbian Government, which they hold responsible for the death of Ferdinand and his wife. This looks like Austria looking for an excuse to crush Serbia
24 July: Serbian Government accepts most of the Austrain demands and suggests that the Court of the Arbitration in the Hague in Holland should decide upon the rest of the demands
25 July: Austria rejects these suggestions and begins to mobilise its troops. Russia (Serbia's ally) tells Austrians that it will also begin to mobilise its troops.
28 July: Austria declares war on Serbia.
30 July: Russia orders mobilisation of its armed forces. Germany warn Russia that if they continue to do so they will be at war (Germany and Russia) Russia continues mobilisation.
1 August: Germany declares war on Russia. Italy declares that it will remain neutral despites of the Triple Alliance with Germany and Austria.
3 August: Germany declares war on France.
4 August: Germany invades Belgium as par of the Schlieffen Plan. Later that day, Britain declares war on Germany
Mobilise: to get armed forces ready for battle.