The Triple Alliance was the military alliance among Germany, Austria-Hungary, and Italy that lasted from 1882 until the start of World War I in 1914. Each member promised mutual support in the event of an attack by any two other great powers, or for Germany and Italy, an attack by France alone. In a supplementary declaration, Italy specified that its undertakings could not be regarded as being directed against the United Kingdom. Shortly after renewing the Alliance in June 1902, Italy secretly extended a similar guarantee to France.
When Germany and Austria-Hungary found themselves at war in August 1914 with the rival Triple Entente of Britain, France, and the latter's ally, Russia, Italy pledged its support to the Central Powers, but subsequently entered the conflict on the side of the Entente against Austria-Hungary in May 1915 and Germany in August 1916.