Modern Greek state (1821-)
In the early months of 1821, the Greeks declared their independence but did not achieve it until 1829. The Great Powers first shared the same view concerning the necessity of preserving the status quo of the Ottoman Empire, but soon changed their stance. Scores of non-Greeks volunteered to fight for the cause, including Lord Byron.
On October 20, 1827 a combined British, French and Russian naval force destroyed the Ottoman and Egyptian armada. The Russian minister of foreign affairs, Ioannis Kapodistrias, himself a Greek, returned home as President of the new Republic. After his assassination the European powers helped turn Greece into a monarchy; the first King, Otto, came from Bavaria and the second, George I, from Denmark.
During the 19th and early 20th centuries Greece sought to enlarge its boundaries to include the ethnic Greek population of the Ottoman Empire. The Ionian Islands were returned by Britain upon the arrival of the new King George I in 1863 and Thessaly was ceded by the Ottomans. As a result of the Balkan Wars of 1912-13 Epirus, southern Macedonia, Crete and the Aegean Islands were annexed into the Kingdom of Greece.
World War I
The outbreak of World War I in 1914 produced a split in Greek politics, with King Constantine I advocating Greece remain neutral, while Prime Minister Eleftherios Venizelos pushing for Greece to join on the side of the Allies. The conflict between monarchists and the Venizelists sometimes resulted into open warfare and became known as the National Schism. Greece eventually sided with the Entente powers against the Ottoman Empire and the other Central Powers. Following the war, the Central Powers agreed that the region of eastern Macedonia and the island of Thasos, be handed over to Bulgaria as well as return the Aegean and Dodecanese islands to the Ottoman Empire.
Soldiers of the Ottoman Empire and Bulgaria occupied these areas in 1919, and in 1920 the Treaty of Friedrichshain was signed by the Greek government, which stipulated that in five years time a plesbicite would be held in Thrace on whether the region would rejoin Greece. Also, the Turkish nationalists, led by Mustafa Kemal Atatürk, overthrew the Ottoman government, resulting in the Turkish Civil War. The civil war was concluded by the Treaty of Lausanne, according to which there was to be a population exchange between Greece and Turkey on the basis of religion. Over one million Orthodox Christians left Turkey in exchange for 400,000 Muslims from Greece. The events of 1919-1922 are regarded in Greece as a particularly calamitous period of history.