The Greek War of Independence from the Ottoman Empire began in 1821 and concluded with the winning of independence in 1828. The first ruler of independent Greece was the governor Kapodistrias, who was murdered in 1831. With the support of England, France, and Russia, a monarchy was established with the signing of the Treaty of London on May 7, 1832 which created an independent Kingdom of Greece. Otto of Wittelsbach, Prince of Bavaria was chosen as its first King in 1833. Otto ruled as an absolute despot, and this led to more and more civil unrest until in 1843 the people and the army of Greece revolted and demanded a constitution. Otto was forced to grant it, and Greece became one of the first European states with a written constitution. Otto's continuing absolutist rule and disrespect for the new constitution led to the deposition of the King in 1862. The Great Powers chose a prince of the Danish House of Glücksburg, a son of King Christian IX of Denmark, as his successor. He became George I, King of the Hellenes.
The Megali Idea (Great Idea), a vision to unite all Greeks living within the borders of the declining Ottoman Empire with the newly independent Greek State, exerted strong influence on the early Greek state. At independence, Greece had an area of 47,515 square kilometers, and its northern boundary extended from the Gulf of Volos to the Gulf of Arta. The Ionian Islands were added in 1864 as a gift from Great Britain to the new King George I; Thessaly and part of Epirus in 1881; Macedonia, Crete, Epirus, and the Aegean Islands in 1913; Western Thrace in 1918; and the Dodecanese Islands in 1947.
Greece entered World War I in 1917 on the side of the Allies. After the war, Greece took part in the Allied occupation of Turkey, where many Greeks (more than two million) still lived. In 1921, the Greek army attacked Turkey from its base in Smyrna (now Izmir), and marched toward Ankara. The Greeks were defeated by Turkish forces led by Mustafa Kemal (later Ataturk) and were forced to withdraw in the summer of 1922. Smyrna was sacked by the Turks, and more than 1.3 million Greek refugees from Turkey poured into Greece, creating enormous challenges for the Greek economy and society and effectively ending the Megali Idea.
Greek politics, particularly between the two World Wars, involved a struggle for power between monarchists and republicans. Greece was proclaimed a republic on March 25, 1924, but George II returned to the throne in 1935, and a plebiscite in 1946 upheld the monarchy. It was finally abolished, however, by referendum on December 8, 1974, when more than two-thirds of the voters supported the establishment of a republic.
Greece's entry into World War II was precipitated by the Italian invasion on October 28, 1940. That date is celebrated in Greece by the one-word reply — ochi ("no") — of Prime Minister Joannis Metaxas to the surrender demand made by Mussolini. Despite Italian superiority in numbers and equipment, determined Greek defenders drove the invaders back into Albania. Adolf Hitler was forced to divert German troops to protect his southern flank and attacked Greece on April 6, 1941. By the end of May, the Germans had overrun most of the country, although Greek resistance was never entirely suppressed. German forces withdrew in October 1944, and the government in exile returned to Athens.
After the German withdrawal, the principal Greek resistance movement, which was controlled by the communists, refused to disarm. A banned demonstration by resistance forces in Athens on December 3, 1944 ended in violence and was followed by an intense, house-to-house battle with Greek Government and British forces. After three weeks, the communists were defeated and an unstable coalition government was formed. Continuing tensions led to the dissolution of that government and the outbreak of full-fledged civil war in 1946. First the United Kingdom and later the United States gave extensive military and economic aid to the Greek government.
Communist successes in 1947–1948 enabled them to move freely over much of mainland Greece, but with extensive reorganization and American material support, the Greek National Army was slowly able to regain control over most of the countryside. Yugoslavia closed its borders to the insurgent forces in 1949, after Marshal Tito of Yugoslavia broke with Stalin and the Soviet Union.
In August 1949, the National Army under Marshal Alexander Papagos launched a final offensive that forced the remaining insurgents to surrender or flee across the northern border into the territory of Greece's communist neighbors. The insurgency resulted in 100,000 killed and caused catastrophic economic disruption. In addition, at least 25,000 Greeks were either voluntarily or forcibly evacuated to Eastern bloc countries, while 700,000 became displaced persons inside the country.
After the 1944-1949 Greek civil war, Greece sought to join the Western democracies and became a member of NATO in 1952. From 1952 to late 1963, Greece was governed by conservative parties: the Greek Rally of Marshal Alexandros Papagos and its successor, the National Radical Union (ERE) of Constantine Karamanlis. In 1963, the Center Union Party of George Papandreou was elected, and governed until July 1965. It was followed by a succession of unstable coalition governments.
On April 21, 1967, just before scheduled elections, a group of colonels led by Colonel George Papadopoulos seized power in a coup d'état. Civil liberties were suppressed, special military courts were established, and political parties were dissolved. Several thousand political opponents were imprisoned or exiled to remote Greek islands. On November 25, 1973, following an uprising of students at the Athens Polytechnic University, General Dimitrios Ioannides replaced Papadopoulos and tried to continue the dictatorship.
General Ioannides' attempt in July 1974 to overthrow Archbishop Makarios, the President of Cyprus, brought Greece to the brink of war with Turkey, which invaded Cyprus and occupied part of the island. Senior Greek military officers then withdrew their support from the junta, which toppled. Leading citizens persuaded Karamanlis to return from exile in France to establish a government of national unity until elections could be held. Karamanlis' newly organized party, New Democracy (ND), won elections held in November 1974, and he became prime minister.
Following the 1974 referendum which resulted in the rejection of the monarchy, a new constitution was approved by parliament on June 19, 1975. Parliament elected Constantine Tsatsos as President of the republic. In the parliamentary elections of 1977, New Democracy again won a majority of seats. In May 1980, Prime Minister Karamanlis was elected to succeed Tsatsos as president. George Rallis was then chosen party leader and succeeded Karamanlis as Prime Minister.
On January 1, 1981, Greece became the 10th member of the European Community (now the European Union). In parliamentary elections held on October 18, 1981, Greece elected its first socialist government when the Panhellenic Socialist Movement (PASOK), led by Andrea Papandreou, won 172 of 300 seats. On March 29, 1985, after Prime Minister Papandreou declined to support President Karamanlis for a second term, Supreme Court Justice Christos Sartzetakis was elected president by the Greek parliament.
Greece had two rounds of parliamentary elections in 1989; both produced weak coalition governments with limited mandates. Party leaders withdrew their support in February 1990, and elections were held on April 8. ND won 150 seats in that election and subsequently gained two others. After Mitsotakis fired his first Foreign Minister, Andonis Samaras, in 1992, Samaras formed his own political party, Political Spring. A split between Mitsotakis and Samaras led to the collapse of the ND government and new elections in September 1993.
On January 17, 1996, following a protracted illness, Prime Minister Papandreou resigned and was replaced as Prime Minister by former Minister of Industry Constantine Simitis. In elections held in September 1996, Constantine Simitis was elected Prime Minister. PASOK won 162 seats, New Democracy, 108.