Prompted in 1878 by Otto von Bismarck to revise the Treaty of San Stefano, the Congress of Berlin proposed and ratified the Treaty of Berlin.

Voided the San Stefano treaty, and was a blow to the Pan-Slavism movement and a humiliation for Russia, caused the decline of Alexander II in Russia

The Russians, led by chancellor Alexander Gorchakov, had manipulated the original treaty after their victory over the Ottoman Empire to create a very large Bulgarian autonomous principality under Turkey's nominal rule, but obviously subject to their influence. This state had access to the Aegean Sea and comprised a very large portion of Macedonia. The other Great Powers, the United Kingdom in particular, could not accept this as it was, in their eyes, a violation of balance of power. The Congress was attended by the United Kingdom, Austria-Hungary, France, Germany, Italy, Russia and Turkey.