Essay on Causes of the First World War - What were ..
Nationalism was also a source of anger between France and Germany as France resented its defeat in the (1870-1871).
Alliances between European nations can also be considered an of World War I.
Causes of World War 1 Essay | Cram
For example, if Germany attacked France, Britain and Russia would help France, and Italy and Austria would help Germany, dragging Europe into a state of chaos and violence.
Militarism was also an underlying cause of World War I.
A German officer once said "in time of peace, prepare for war," and that is exactly what European nations did, eventually leading to the Great War.
Without a doubt, the one underlying cause of the three described above that was most responsible for World War I was the system of alliances.