Dual Alliance (1879)

The Dual Alliance was a defensive pact between Austria-Hungary and the German Empire, created on October 7, 1879. It stipulated that each country would come to the aid of the other if either were attacked by Russia. Furthermore, if either Austria-Hungary or Germany were attacked by another European power (generally understood to be France), the other ally would pledge at least neutrality. If the attacking power was supported by Russia, the terms of the alliance obligated both Austria-Hungary and Germany to provide military assistance.

The alliance was forged by Otto von Bismarck, the Chancellor of Germany, following the Congress of Berlin in 1878. Bismarck sought to prevent Austria-Hungary from allying with Russia against Germany, and also to secure Austria-Hungary's support in case of a future war with France. The Dual Alliance was kept secret for several years to avoid alarming other European powers, particularly Russia.

The Dual Alliance was a key element of Bismarck's system of alliances aimed at maintaining peace in Europe by isolating France. It formed the basis of the Triple Alliance in 1882, when Italy joined the Dual Alliance. The Dual Alliance lasted until the end of World War I in 1918, when both Austria-Hungary and the German Empire collapsed.