In 1867 Russia resolved to dispose of its possessions on the western hemisphere by selling Alaska, a territory covering 590,884 square miles, to the United States. In the same year a Slavophil Congress was held at Moscow with the czar's approval. The object was said to be to unite all the nations of Slav origin by a bond of friendship; but the real purpose was to bring them under the rule of the czar. This was apparent when it was resolved to send emissaries among the Slavs under Turkish rule. They met with encouragement in Montenegro, Bulgaria, Bosnia, and Herzegovina. General Ignatieff, the Russian ambassador at Constantinople, thought that this might be the means to bring about the longed-for annexation of the old Czargrad. He worked upon the Turkish subjects belonging to the Greek Church, but showed his hand when, under his decision, the Bulgarians were released from the (p. 231) authority of the Patriarch of Constantinople. In 1875, the Bulgarian Christians rose against the Turkish tax-farmers. The revolt was fanned by the Russian emissaries, and it spread to Servia and Montenegro. Ignatieff did not think that the time was ripe and interfered; but he threatened the Sultan with European intervention and Abdul Aziz granted the insurgents the privileges enjoyed by the Christians in Turkey. Austria looked with apprehension upon the increasing influence of Russia in Turkey, and suggested drastic reforms in a note addressed to the powers on December 30, 1875. It was approved and presented to the sultan by the five great European powers. Abdul Aziz quietly accepted it. This was not what the Russian Slavophils expected, and they incited the Servians to revolt. A religious insurrection followed which was put down by the Turks with such cruelty that it aroused universal indignation in Europe, especially in Russia. In Constantinople the Turks were indignant at the sultan's evident fear of Ignatieff. The situation became so alarming that Great Britain assembled a fleet in Besika Bay. The triple alliance, Russia, Austria and Prussia, demanded of the sultan an armistice and the execution of reforms under foreign supervision. The situation changed by a revolution in Turkey on May 29, 1876, when Abdul Aziz was assassinated and succeeded by his nephew Murad V. Russia felt that war was inevitable and approached Austria with proposals to take joint action. The reply was that Austria could not permit the creation of a Slav state on the frontier and that, if any changes were made in the Balkans, Austria must receive compensation. This was (p. 232) admitted by Russia. A number of Russian officers took service in Servia, among them General Chernaiev, who had gained distinction in Central Asia. Montenegro declared war against Turkey on July 2, 1876.