Causes of World War I
The war between France and Prussia (the future German Empire) that lasted from 1870 to 1871 ended with a humiliating defeat for France.
Accession of Wilhelm II to the German Throne
With the accession of Wilhelm II to the German throne in 1888, the German foreign policy became more bellicose.
Russo-Japanese rivalry over Manchuria and Korea reached its height with the Russo-Japanese War (1904-1905).
German militarism and especially the buildup of naval power convinced Great Britain that Germany may soon establish itself as a dominant power on the Continent.
The Moroccan Crises - the Tangler Crisis (1905-1906) and Agadir Crisis (1911) - brought the European powers on the brink of war.
Bosnian Annexation Crisis
In 1908, Austria-Hungary decided to annex Bosnia and Herzegovina that was formally an integral part of the Ottoman Empire.
The Italo-Turkish War that took place between 1911 and 1912 did not pose any major threat to peace in Europe.
In 1912, Serbia, Greece, Montenegro and Bulgaria formed the Balkan League, a military alliance against the Ottoman Empire.
On July 23, Austria-Hungary presented an ultimatum to Serbia.