Greek foreign policy in the crucial period 1897-1922 was inspired by the central ideal of the Great Idea that had sparked Greek nationalism since 1840, and had become dominant from the 1880s onwards.

Two major theories developed in this period concerning the Great Idea, theories that led Greek foreign policy in two different directions and representing two different views on national integration: the Venizelist and the anti-Venizelist.

The former expressed the views of Greek nationalists and and nationalists of the New Territories annexed after the victorious Balkan Wars, whereas the latter expressed the views of Old Greece.
Venizelism believed in the 'Greater Greece of the two continents and of the five seas', with a distinctly nationalistic note, and projected the policy that meant the expansion of the Greek territory and the inclusion of Greek-speaking populations into the Greek state.
Anti-Venizelism opposes such expansionism, being all too aware of the sacrifices required for its implementation. Instead, it proposed a 'small but honourable Greece', with reference to the state before 1912. In the period 1916-17 the Schism, that was caused by the disagreement of the leaders of the two blocs for the position of Greece in the First World War, led to the creation of two states: that of Athens and that of Thessaloniki.

The opposition of the two blocs, related to deeper socio-political contrasts in Greece of that period, first became manifest upon the occasion of the dilemma that Greece had to face concerning her position in the First World War, whereas later on it acquired a more tangible form in the personal conflict between King Constantine and the Prime Minister Eleftherios Venizelos, divided the Greeks and led to the crisis of the National Schism that culminated in the period 1916-17.