The organisation, however, of the regular forces (_Nizam_), which were to take their place, being only half complete, it was just at the moment when the military organisation of the empire was undergoing a radical transformation that the new Sultan was called upon to face all the complications of internal revolution and foreign wars that confronted him on his accession. Mahmoud, however, set resolutely about the task, and a certain measure of success attended his first efforts. The Pashas of Widdin and Janina were successively reduced to subjection, and by the help of the Pasha of Egypt who had not yet thrown off his allegiance, the Morea was reconquered by the troops of Ibrahim Pasha, and Greece would undoubtedly have been restored to her position as the Western horn of the Ottoman Crescent but for the forcible interference of Europe and the military expedition of Marshal Maison. By a protocol, signed at St Petersburg, on 4th April 1826, Greece was declared an autonomous and vassal State; but after the rejection by the Sultan of the collective mediation of the four Great Powers (5th February 1827), Austria, France, Great Britain and Russia (Protocol of London), and the destruction by the allied forces, without the formality of a declaration of war, of the Turkish fleet at Navarino (1827), immediately followed by a declaration of war on the part of Russia, and the campaigns of Diebitch in Europe, and Paskiewitz in Asia Minor, terminating in the disastrous Treaty of Adrianople (14th September 1829), Mahmoud had no choice but to consent in the following year (1830) to the creation of Greece into an independent kingdom, an arrangement confirmed by the Treaty of London on the 13th July 1841. The still more serious revolt of Mehemet Ali—imperilling as it did not only the integrity of the empire, but the solidarity of Islam—immediately followed. On the Ottoman sovereign refusing to concede the government of Syria to Mehemet Ali, in return for his services in the campaign against Greece, the latter, picking a quarrel with the governor of the coveted province, quickly invaded Syria, and, defeating the Ottoman troops in a great battle at Konia, compelled the Sultan to agree to a truce (credited with the name of peace), whilst both sides prepared for an early resumption of hostilities. When this took place the Egyptian troops were again successful in a decisive battle at Nezib (24th June 1839), which placed the whole of Syria, up to the walls of Acre, in the possession of the victorious Pasha of Egypt. Russia was, of course, too alert in following the traditional policy in regard to Turkey not to profit by these distractions, and it was at this mortal crisis of the Ottoman Empire that she stepped in and secured the secret clauses of the Treaty of Unkiar Iskelessi (8th July 1833), by which she bound Turkey to an offensive and defensive alliance that was to last for eight years, and to exclude all flags but her own from passing through the Bosphorus.