The Reinsurance Treaty was a diplomatic agreement between the German Empire and the Russian Empire that was in effect from 1887 to 1890. The existence of the agreement was not known to the general public, and as such, was only known to a handful of officials in Berlin and St. Petersburg. The treaty played a critical role in German Chancellor Otto von Bismarck's network of alliances and agreements, which aimed to keep the peace in Europe as well as maintaining Germany's economic, diplomatic and political dominance. It helped calm tensions between both Russia and Germany.
The treaty provided that both parties would remain neutral if the other became involved in a war with a third great power, with the exception of if Germany attacked France or if Russia attacked Austria-Hungary.