Military history of Italy during World War I

Although Italy was a member of the Triple Alliance, it did not join Germany and Austria-Hungary when the conflict started in 1914, arguing that the war had been initiated by the two Central Powers and that the Triple Alliance was a defensive pact. Italians protested for the lack of consultation before Austria issued the ultimatum to Serbia and invoked a clause of the Triple Alliance, according to which both Italy and Austria-Hungary were interested in the Balkans and whoever changed the status quo in the region had to compensate the other; Austria-Hungary refused any compensation before the end of the war.

Source: Wikipedia — Military history of Italy during World War I (CC BY-SA 4.0)