Negotiations proceeded slowly, but, on July 6, 1827, Great Britain, France and Russia bound themselves by treaty to obtain the autonomy of the Morea. Moreover, in a secret article, it was provided that an armistice was to be proposed to both sides to be enforced by such means as might "suggest themselves to the prudence of the High Contracting Parties." Three months later, on October 20, the allied fleets of the three Christian Powers, under the command of Codrington, the senior admiral, were face to face with the Mussulman armada in the Bay of Navarino. Immediate hostilities were probably not intended, but a dispute about the position of a fire-ship led to an exchange of shots. Before nightfall the "untoward event" had come to pass--the Turkish and Egyptian fleets had been destroyed completely. Mahmud in his fury proclaimed a holy war, and declared null and void the convention of Akkerman, which he had recently concluded with Russia for the settlement of certain points, long in dispute between the two Powers. Canning was dead and Wellington was determined to abstain rigidly from anything in the nature of hostile action against Turkey. Nevertheless, under the conditions which had been created by Canning's departure from the traditional policy of his party, he could do nothing to prevent Nicholas from appealing to the last argument of princes. On May 6, 1828, the Russians crossed the Pruth and the war began, which British and Austrian diplomacy had always striven to avert. The Turks, however, in a struggle with their hereditary foes displayed unexpected powers of resistance, and it was not until September 14, 1829, when Constantinople appeared to lie at the mercy of the invaders, that peace was concluded at Adrianople. In accordance with his promises to the Powers, Nicholas had exacted no cession of territory in Europe. But Turkey had been compelled to grant a practical independence to the Danubian principalities, to pay a heavy war indemnity and to surrender to Russia Anapi and Poti on the eastern shore of the Black Sea. Moreover, the Sultan was forced to acknowledge the complete independence of Greece, which was placed under the guarantee of Great Britain, France and Russia. The loss of the Morea was a serious blow to the Porte. Not only was the Turkish navy deprived of its finest recruiting ground, but the countenance given by the Powers to the rising of the Greeks necessarily had a most disturbing effect upon all the Christian subjects of the Sultan.