Lord Byron died,[51] and Shelley wrote for the Greek cause. Lord Cochrane and Sir Richard Church fought, while the German poet, Müller, and the Swiss Eynard, warmly upheld the cause of the oppressed Greeks. Notwithstanding this help, the Greeks were far from fortunate, and the Sultan, with the help of the Egyptians, captured Athens. But their brave defence of Missolonghi aroused the sympathies of the European Powers. _Nicholas I._ (1825–1855). On the death of Alexander I. the Holy Alliance vanished (1825), and Nicholas I. ascended the throne (1825–1855). Now the Greeks appealed to England for help, and Canning[52] saw that it was the best policy for England to assist Greece in order to control the ambitious plans of Russia. Accordingly he sent the Duke of Wellington as the English representative, and a protocol was signed at St. Petersburg by which Greece was to remain tributary to the Sultan, but to be independent as regards commercial relations. This protocol developed into the Treaty of London, between England, France, and Russia, by which the three Powers bound themselves to act as mediators in the Eastern question. The mediation of the Powers was rejected by the Porte, but accepted by the Greeks. The result was that the Turko-Egyptian fleet was totally destroyed at the Battle of Navarino by the allies, and the Sultan retreated from the Morea. Canning’s death in 1827 gave England an opportunity of retiring from active participation in the alliance, especially as she regarded the Battle of Navarino as an “untoward event,” so Russia and Turkey were left alone in conflict. This, in my opinion, was a half-hearted policy on the part of England, although the Cabinet at that time could do no other, because their tenets would not allow them to help a revolutionary people against a country governed by a legitimate sovereignty. Now had the long-wished-for opportunity arrived for Russia to carry into effect on Turkey her long-cherished designs. Diebitch, a Russian general, crossed the Balkans, and soon captured Adrianople; while Paskevitch took Kars and Erzeroom in Asia. These successes resulted in the Treaty of Adrianople (1829), between Russia and Turkey. By the treaty[53] Russia gave back almost all her conquests to Turkey, only retaining the ports of Anapa and Poti, on the eastern coast of the Black Sea, and the Protectorate powers of the Czar over the Danubian Principalities were confirmed and extended. In return Turkey acquiesced in all the provisions of the London Conference. This made Greece practically an independent state. Nicholas pursued the policy of Alexander I. with regard to the Asiatic boundaries, and successfully carried on a war with Persia from 1826 to 1828 which was terminated by the Treaty of Turkmantchai (1828), Russia receiving the provinces of Erivan and Nakhitcheven. This was the period of the expansion of Russia, and the first appearance of Russia as a real rival of Great Britain.