The Triple Alliance was a military alliance between Germany, Italy, and Austria Hungary that lasted from 1882 until the beginning of World War I in 1914. Each member of the alliance promised mutual support in the event of an attak by any two Great Powers, or in the cases of Germany or Italy, an attack by France alone. Italy declared that her undertakings could not be considered as hostile against the United Kingdom though, and secretly made a similar agreement with France after the renewal of the alliance in 1902.

Italy's conjuction with the German-Austrian dual alliance was triggered by anger at France for the French seizure of Tunisia in 1881, which Italy had considered to be a prime place for a potential colony. Italian public opinion was opposed to an alliance with Austria-Hungary though, who had formerly been a past enemy of Italian unification.

In the years preceding WWI, it was predicted that Italy would break away from the allinace, and these beliefs were strengthened by Italy's invasion of Tripoli, which brought it into conflict with the German-backed Ottoman Empire. When Germany and Austria-Hungary found themselves at war with the Triple Entente in 1914, Italy pledged it's support to the Central powers. Italy entered the conflict alongside the Entente in Hungary in May 1915 and Germany in August 1916 though. Italy's reason for not joining the Central Powers was that the Triple Alliance was a defensive alliance, and Germany and Austria Hungary were enterinmg the war offensively.

A map of pre WWI Europe, Triple Alliance countries in red