The vast majority of the territory of present-day Greece was at some point incorporated within the Ottoman Empire. The period of Ottoman rule in Greece, lasting from the mid-15th century until the successful Greek War of Independence broke out in 1821 and the First Hellenic Republic was proclaimed in 1822, is known in Greece as Turkocracy (Greek: Τουρκοκρατία, romanized: Tourkokratia, lit. 'Turkish rule'). Some regions, like the Ionian islands and various temporary Venetian possessions of the Stato da Mar, were not incorporated in the Ottoman Empire. The Mani Peninsula in the Peloponnese was not fully integrated into the Ottoman Empire, but was under Ottoman suzerainty.
The Eastern Roman Empire, which ruled most of the Greek-speaking world for over 1100 years, had been fatally weakened since the Fourth Crusade of 1204. Having defeated the Serbs, the Ottomans captured Constantinople in 1453 and soon advanced southwards capturing Athens in 1456 and the Peloponnese in 1460. By the early 16th century, all of mainland Greece and most of the Aegean Islands were in Ottoman hands, excluding several port cities that were still held by the Venetians (notably Nafplio, Monemvasia, Parga and Methone). The mountains of Greece remained largely untouched and were a refuge for Greeks who desired to flee Ottoman rule and engage in guerrilla warfare. The Cyclades islands were annexed by the Ottomans in 1579, although they had been under vassal status since the 1530s. Cyprus fell in 1571, and the Venetians retained Crete until 1669. The Ionian Islands were never ruled by the Ottomans, with the exception of Kefalonia (from 1479 to 1481 and from 1485 to 1500), but remained under the rule of the Venice. It was in the Ionian Islands that modern Greek statehood was born, with the creation of the Republic of the Seven Islands in 1800.