The first Greek president was elected in 1827, before actual independence. Ioannis Kapodristrias was from the island of Kerkyra (Corfu), and had been the foreign minister of the Russian Tsar Alexander I.
The temporary capital (preceding official independence) was the harbor town on the island of Aegina in the Saronic Gulf (1826-29), to be succeeded by the port of Nafplio in the Argolid (Peloponnese, once independence was finalized. Kapodristrias, who was found too autocratic, was assassinated in 1831 by Maniot chieftains (the Maniots being clansmen of the mountainous Mani region, notorious for their long feuds, carried out with much shooting between tall stone towers).
The same players in the Battle of Navarino, Russia, France, and Britain, intervened and set up a monarchy with a non Greek president (supposedly to prevent factionalism), the 17 year old Prince Otto of Bavaria, who assumed office at the beginning of 1833, with the new kingdom, established by the London Convention of 1832, consisting of Central Greece (also known as Sterea Elladha, and including the mainland area south of Ipiros and Thessaly,), the Peloponnese, and the Cyclades and Sporadhes island groups.
The young Bavarian king, whom the Greeks called Otho, set up a little oligarchy with his Bavarian friends the main government appointees; he moved the capital to Athens in 1834. By 1843, former freedom fighters were holding demonstrations in Athens, demanding a constitution, which was delivered by the young Otho, upon which his friends were thrown out and freedom fighters took over.
In 1862, King Otho was deposed in a bloodless revolution by a new class of rebels—graduates from the Athens University, which had been founded in 1837, but the same year the British slipped a young Danish prince (William, who became George I ) on the throne, in a sleight of hand that involved their return of the Ionian islands, (which had been a British protectorate since 1815) to Greece.
George I ruled for a half century, a reign which established stability to Greece, with a constitution calling for democratically elected representatives (1864). In 1881, Thessaly and part of Ipiros were added to the Greek state, as a result of a Russo-Turkish war. In 1896, the first Olympic Games were held , in Athens.
Meanwhile, Crete was still fighting for its independence from the Ottoman Empire, with an uprising in 1866-68 crushed by the Sultan, and another in 1897.
The Greek Prime minister declared war on Turkey and even fostered an attempt to invade Turkey. It was only through intervention by the Great Powers that disaster was averted. Crete was under international governance until 1913 (though the Greek stateman, Eleftherios Venizelos, announced its union with Greece in 1905), when it was finally officially united with Greece. Venizelos became Greek Prime Minister in 1910, and was later the major player in the ‘Katastrofi’ of 1922 (see below).