The influence of Great Britain was now paramount at Constantinople. The sultan was satisfied with his ally, since he knew that of all the Powers he had least to fear from this state, which had no territories in that part of the Mediterranean and was committed to the preservation of his rule as a means of keeping Russia away from the Bosphorus. To justify herself for defending the Turk, Great Britain gave the world assurances that the sultan was about to become good. Under her insistance a series of reforms was announced, but they did not go far in the realization. Some of the promises referred to the government of the Balkans, but they were as fruitless as the others. Meanwhile French and British merchants found large profits in Turkish trade. The tsar was humiliated by his loss of influence in the Southeast, and in 1877 he began another war against Turkey. He thought the time favorable for such action. Impeded for a while at Plevna, in Bulgaria, he at last swept the enemy before him and took Adrianople on January 16, 1878. His successes created great enthusiasm among the Serbs, Bulgars, and Rumans, who flocked to his victorious standard. The panic-stricken sultan sued for peace and at San Stefano signed a treaty which granted all that was demanded of him. Serbia, Montenegro, and Rumania were recognized as completely independent, Bulgaria as an autonomous tributary province, and Bosnia and Herzegovina were assured of important administrative reforms. Russia was awarded some territory not strictly in the Balkans, but her greatest gain was the prestige she now had as liberator of Christian states. The treaty of San Stefano alarmed Great Britain and Austria, both of whom felt that they had major interests at stake. They got a congress of the Great Powers to meet at Berlin, 1878, which revised the treaty in what they were pleased to call the interest of European peace. Complete independence was announced for Serbia, Rumania, and Montenegro, and the sultan accepted the fact of their perfect sovereignty. By the treaty of San Stefano Bulgaria was to include Macedon and eastern Rumelia, making one great buffer province between the Turkish and the Christian states. The three parts were now left distinct, Bulgaria proper being autonomous but under Turkish suzerainty, and the other two less independent.