During the heyday of the Great Idea the Greeks developed a conception of their national identity which included the following features:
(a) The Greek nation are a people who lived for millennia in their Mediterranean territory. Present-day Greeks are the descendants of the Hellenic heroes, Plato, Sophocles, Alexander and the Greek-speaking Christians of Byzantium. They are to be identified not by reference to citizenship of the existing Greek State, but by reference to a distinguished civilisation and language to which they are all the rightful heirs.
(b) The Greek nation is much larger than the modern Greek State. The latter is that part of the Hellenic and Christian Orthodox world which has been liberated from (mostly Ottoman) domination by the sacrifice and heroism of Greek people.
(c) It is the patriotic duty of all 'true' Greeks to work for the liberation of all historically Greek lands, now inhabited by Greeks under foreign rule. And it is a 'prescription of history' (a meaningless phrase which has enjoyed wide currency among history-conscious Greeks) that all foreign-dominated Greek territory will eventually become united with the free Greek State.
Thus, to be a 'true' Greek, one would have to conceive of oneself as a member of a great nation only a part of which having, as yet, been redeemed and organized as a free national State; and further, to believe that this national State must grow steadily until it encompasses the whole of the ancient and Byzantine Hellenic world. Greek children at school were taught extensively their history (or an official version of it), ancient, medieval and modern; and modern history was taught as a record of the gradual fulfilment of national aspirations, mainly, by fighting against Ottoman Turkish conquerors. So, by a combination of various historical factors, state-controlled education, propaganda and political demagogy, Greek nationalism and patriotism came to mean by the 1860s: pride in being a member of a superior nation, belief in the necessity of extending the boundaries of the Greek State to include all historically Greek lands, and consequently the assertion of the duty to support a just struggle against the Turkish conquerors who have for long held by force sacred national territory. [from Zenon Stavrinides, The Cyprus Conflict, pp 19-20]