三帝同盟
The League of the Three Emperors having fallen apart, Bismarck negotiated the Dual Alliance with Austria-Hungary, in which each guaranteed the other against Russian attack. He also negotiated the Triple Alliance in 1882 with Austria-Hungary and Italy, and Italy and Austria-Hungary soon reached the "Mediterranean Agreement" with Britain. Attempts to reconcile Germany and Russia did not have a lasting effect: the Three Emperors' League was re-established in 1881 but quickly fell apart, ending Russian-Austrian-Prussian solidarity, which had existed in various forms since 1813. Bismarck therefore negotiated the secret Reinsurance Treaty of 1887 with Russia, in order to prevent Franco-Russian encirclement of Germany. Both powers promised to remain neutral towards one another unless Russia attacked Austria-Hungary. However, after Bismarck's departure from office in 1890, the Treaty was not renewed, thus creating a critical problem for Germany in the event of a war.