The Triple Alliance was a military alliance among Germany, Austria–Hungary, and Italy. It was seen as many as the opposing alliance to the Triple Entente, between Britain, France, and Russia. It lasted from 20 May 1882 until the aftermath of the War of 1914. Each member of the alliance promised mutual support in the event of an attack by any other great power, or, in the case of Germany and Italy, an attack by France alone.
As was seen during the War of 1914, Italy would not join Austria-Hungary in its war against Serbia and Russia due to the fact that Austria-Hungary declared war first, and was thus not a defensive war. Germany was unable/unwilling to go to war primarily because they would be able to claim a swift victory against France with such a fortified border and no other available way to invade easily. This would thus mean a prolonged war with both France and her ally Russia, and would not go to war. Austria was left to fight alone, and eventually lost the war later that year. The Alliance fell apart in 1915, and the three major powers were left to seek alliances elsewhere.