It was at this period that Germany had failed to crush Russia in the struggle on the Vilna, and, in accordance with her usual strategy when one plan failed, another was undertaken. It seemed to her, therefore, that the punishment of Serbia would make up for other failures, and moreover would enable her to assist Turkey, which needed munitions, besides releasing for Germany supplies of food and other material which might come from Turkey. They therefore entrusted an expedition against Serbia to Field Marshal von Mackensen, and had begun to gather an army for that purpose, north of the Danube. This army of course was mainly composed of Austrian troops, but was stiffened throughout by some of the best regiments from the German army. To assist this new army they counted upon Bulgaria, with whom they had already a secret treaty, and in spite of the falsehoods issued from Sofia, the Bulgarian mobilization was meant for an attack on Serbia. The condition of affairs was well understood in Russia. On October 2, 1915, M. Sazonov, Russian Minister of Foreign Affairs, issued the following statement: “The situation in the Balkans is very grave. The whole Russian nation is aroused by the unthinkable treachery of Ferdinand and his Government to the Slavic cause. Bulgaria owes her independence to Russia, and yet seems willing now to become a vassal of Russia’s enemies. In her attitude towards Serbia, when Serbia is fighting for her very existence, Bulgaria puts herself in the class with Turkey. We do not believe that the Bulgarian people sympathize with the action of their ruler therefore, the Allies are disposed to give them time for reflection. If they persist in their present treacherous course they must answer to Russia.” The next day the following ultimatum from Russia was handed the Bulgarian Prime Minister: