According to watchtutorials, the London Protocol (1830) gave rise to the Kingdom of Greece, territorially limited between the Gulf of Arta and that of Volos, while Great Britain retained possession of the Ionian islands (ceded to the Greeks only in 1863). The 1832 convention attributed the crown to Otto of Wittelsbach, son of Louis I of Bavaria. The new state, deprived of the most productive regions (Thessaly, Macedonia, Crete), also had to shoulder the debts of the war of liberation, becoming economically dependent on London. Surrounded by Bavarian officials, Otto ruled autocratically, drawing the hatred of his subjects until 1844, when he was forced to grant a Constitution. He therefore tried to take advantage of the crisis in Crimea (1853-56) to achieve territorial enlargements at the expense of the Ottoman Empire,
Deposed Ottone from a military coup in 1862, a constituent assembly elected King George I, son of Christian IX of Denmark, on the designation of France, England and Russia, and established a regime of liberal democracy (1864). The first impetus to economic and civil development was given to the country by the government action of Charilaos Trikupis (1882-90), but the modest resources of Greece did not withstand the effort aimed at realizing the aspirations of irredentism: intervention in the conflict Balkan of 1885-86 failed and the war against the Turks for the liberation of Crete (1897) ended in defeat. A period of relevant events corresponded to the government of Eleftherios Venizelos, who came to power in 1910, who promoted an effective constitutional reform (1911) and the reconstruction of the armed forces and, in the aftermath of the Balkan wars, ensured the country, with the Treaties of Bucharest and London (1913), important territorial acquisitions (Giannina, Salonica, Kavalla, Crete and the Aegean islands except the Dodecanese, which became an Italian possession). The First World War saw the clash between the Crown, in favor of the Central Powers, and the Liberal Party of Venizelos, in favor of the Entente. After trying to force the will of King Constantine I, in 1916, with the support of the Anglo-French, Venizelos led an armed revolt, constituting a new army and a provisional government, forcing the sovereign to abdicate (1917) and pushing the his successor Alexander at the declaration of war on the Central Empires, Turkey and Bulgaria. The Treaty of Sèvres (1920) assigned to Greece eastern Thrace up to the Black Sea, the peninsula of Gallipoli and the territory of Smyrna.
Despite international successes, Venizelos was defeated in the elections of 1920, when King Alexander died, a plebiscite restored the deposed King Constantine to the throne. The occupation of Smyrna by Mustafa Kemal’s Turkey (September 1922), broke the idea of expansion in the Anatolian peninsula, which had had one of the main supporters in Venizelos, and forced Constantine to abdicate in favor of his son George II. In 1923 the Peace of Lausanne closed the conflict with Turkey, imposing territorial sacrifices on Greece; the Greek-Turkish agreement established the principle of the exchange of alloglot populations and, while posing the problem of accommodating more than 1,200,000 Greeks returning to their homeland, it consolidated national unity.
In 1924, a revolution promoted by the military spheres overthrew the monarchy and established, by vote of the national constituent assembly, the republic; in the new regime the liberal-national current of Venizelos succeeded in prevailing in 1928, which implemented the reintegration of Greece into European and Mediterranean politics through a series of agreements with Italy (1928), Yugoslavia (1929) and Turkey (1930). However, he was not successful in consolidating republican democracy and in 1933 the electoral victory of the pro-monarchist opposition caused the fall of his ministry. After the attempt of the revolutionary reconquest of power carried out in 1935 by the Venizelists, a coup d’état restored the monarchy.