Reinsurance Treaty en.wikipedia.org The Reinsurance Treaty of June 18, 1887 was an attempt by German Chancellor Otto von Bismarck to continue to ally with Russia after the League of the Three Emperors had broken down in the aftermath of the 1885 Serbo-Bulgarian War. Facing the competition between Russia and Austria–Hungary on the Balkans, Bismarck felt that this agreement was essential to prevent a Russian convergence toward France and to continue the diplomatic isolation of the French so ensuring German security against a threatening two-front war. He thereby hazarded the expansion of the Russian sphere of influence toward the Mediterranenan and diplomatic tensions with Vienna.