During the Russo-Turkish War, April, 1876, to February, 1877, the causes and results of which will be considered in another place, Germany maintained the strictest neutrality, so strict in fact that at its conclusion Germany was chosen as mediator. To this part the young empire adhered most carefully during the Congress of Berlin, June to July, 1878, and, difficult though it was, showed the strictest impartiality. At the same time it refused to gain any profit from the readjustment which resulted. In spite of this, however, it received little appreciation on the part of Russia, which apparently had expected a more active display of gratitude on the part of Germany for its own friendly neutrality during the Franco-Prussian War. In a way this marks the beginning of a strong anti-German feeling in Russia, which by 1879 had grown strong enough to make a war between the two countries seem possible. Bismarck immediately took the necessary steps to insure Germany against such a possibility by concluding an alliance with Austria, October 7, 1879, at Gastein. In this he was bitterly opposed by William I, whose personal feelings were leaning much more toward Russia than Austria. However, a threat on the part of the chancellor to resign brought this rapidly aging emperor to terms.
The Austro-German alliance was defensive only. It stipulated that in case of an attack by Russia on either contracting party the other was to assist with its entire forces. In case of an attack by any other power only friendly neutrality was to be observed, except if such a power was in any way supported by Russia, when the first stipulation was to take force.
Three years later, in 1882, Bismarck strengthened Germany's international position by overcoming Italy's enmity against Austria to the extent of inducing the southern kingdom to join in this defensive alliance, which from then on was known as the "Triple Alliance," and which endured until Italy's declaration of war against Austria in 1915. The chancellor had now succeeded in placing the keystone in Germany's defensive bulwark. He had to fear no longer the possibility of a joint attack by Russia and France. For the powerful triple block of Central Powers would make any joining of forces by these two countries impossible.