Signet), and was sent with Anthony Merry on a mission to Denmark later that year. His first trip to Constantinople came in 1808, when he accompanied the mission of Robert Adair that restored peace between Britain and the Turks. When Adair left Constantinople in 1810, Canning became Minister Plenipotentiary, and it was Canning who helped mediate the Treaty of Bucharest between the Ottomans and Russia on 28 May 1812. Canning returned to London later that year, and helped to found the Quarterly Review. In June 1814 was appointed Envoy Extraordinary and Minister-Plenipotentiary to Switzerland, where he, along with the other allied representatives, helped negotiate Swiss neutrality and a new Swiss federal constitution. In October he went to Vienna, where he acted as an aid to Lord Castlereagh, the British representative at the Congress of Vienna. After the negotiation of Swiss neutrality in 1815, Canning's role there became dull to him, but he stayed until 1819, when he was recalled and sent to Washington as Envoy Extraordinary and Minister-Plenipotentiary to the United States. Although he hoped for major accomplishments in Washington that would allow him to move up to a larger position, he was largely unsuccessful. The initiative of his cousin George, this time as Foreign Secretary, for a joint Anglo-American guarantee of Latin American independence, led to the promulgation of the Monroe Doctrine. In 1820 Canning was made a member of the Privy Council. Canning returned to London in 1823, and the next year was sent on a mission to Russia, where he negotiated a treaty on the border between Russian and British North America, but failed to come to any agreement regarding the Greek Revolt. Later in February 1825 he concluded a treaty with Russia on the north-west American frontier (Treaty of Saint Petersburg (1825)). In 1825, Canning was returned to Constantinople, this time as Ambassador. He fled the city following the Battle of Navarino in 1827, but after a brief return to London he, along with the French and Russian ambassadors who had also fled, set up camp at Poros. In 1828 he and the other ambassadors participated in the Conference of Poros, which recommended to their respective governments the establishment of a separate Greek state, including the islands of Crete, Samos, and Euboea. Although he had been encouraged in this generous position towards the Greeks by his superior, Lord Aberdeen, this move was disavowed by the government,