These repeated successes of the Russians began to cause alarm to Austria and Prussia, who by no means wished for the undue aggrandizement of their neighbour. They therefore attempted negotiations with Russia for mediation on behalf of the Ottoman Empire. But the Empress Catherine obstinately resisted anything in the way of interference by other Powers, and made it known to the Sultan that terms of peace must be settled with herself alone. In his desperation the Sultan proposed to Austria a joint partition of Poland as a bribe for assistance against Russia, oblivious of the fact that he had entered upon war with Russia on behalf of Poland. The offer was declined by the Emperor, not because he had any objection to a scheme of plunder, but because he did not consider the Porte to be in a position to become an effective partner in such a scheme. As a matter of fact, Austria, Russia, and Prussia were continually negotiating schemes for the dismemberment either of Poland or Turkey, as might be most convenient to them. At the end of the campaign of 1771 an armistice was agreed to between Russia and the Porte, and the greater part of the following year was occupied in discussing terms of peace at a conference or congress at Bucharest. An ultimatum was eventually presented by Russia, embodying terms of what might seem to be a very moderate character, in view of the great success of her armies and the extent of territories which they had practically conquered. The Sultan himself and his Grand Vizier and principal ministers and generals were in favour of accepting the terms as offered, but the Mufti and the whole body of the ulemas were vehemently opposed to them. The Divan therefore rejected them and war was renewed. As these terms did not substantially differ from those which were accepted two years later, it is not worth while at this stage to explain them. Meanwhile there had been for more than a year a suspension of hostilities, and a breathing time had been afforded to the Porte, during which strenuous efforts were made for another campaign. At the end of 1772, Mouhsinzade Pasha, who had so distinguished himself in the defence of the Morea, was again appointed Grand Vizier. He infused new vigour into the army. In the spring of 1773, when the negotiations at Bucharest were brought to a conclusion, hostilities were recommenced. The campaign in Europe, in this year, was confined within the quadrilateral formed by the fortresses in Silistria and Rustchuk on the Danube, the city of Varna on the Black Sea, and the great fortress of Schumla to the north of the Balkan range. There were several engagements between divisions of the two armies in this district, in which the Turks were generally worsted, but these victories were not of much avail to the Russians so long as the three great fortresses of Silistria, Varna, and Schumla remained in the hands of the Turks.