The Central Powers form Triple Alliance

The political agreement that led to the outbreak of WW I came because Germany, the rising empire; Austria-Hungary, the fading power; and Italy, the constant presence all decided they could gain more by putting aside their difference and working with each other. Austria and Germany wanted the Balkans, while Italy wanted to gain some overseas colonies in Greece. A pact that united them in all conflicts was the perfect mechanism for realizing those goals.

On this day, May 20, in 1882 Germany, Austria-Hungary and Italy formed the military Triple Alliance, promising mutual aid in case of an attack by the other European powers.

The Triple Alliance did not have to wait long to activate its obligations. When a Serbian student Gavrilo Princip assassinated the heir to the Austrian throne, Archduke Franz Ferdinand, Austria declared war on Serbia, which brought Russia into the war from the east. Before Russia could mobilize, however, the the Triple Alliance launched a preemptive attack on France, which then brought Britain in to the defense of its neighbor, and WW I was on.