Greek claims concerning Ionia, as presented in the Paris Peace Conference, met with opposition not only from the Turkish quarter but also due to disputes among the Allies.

The Italians in particular were negative, fearing the competition of a reinforced Greek presence in the eastern Mediterranean. They invoked the Treaty of St Jean de Maurienne of 1917, according to which Smyrna and Iconium were conceded to them, in order to give up their intention of signing a separate peace treaty with Austria. The Americans, in turn, contested the credibility of the very will of the Greeks of Ionia to unite with Greece and estimated that the Asia Minor coast was organically, geographically and economically linked with Anatolia, and should be autonomous.

The discontent of the British and the French caused by the coercive claims of Rome on the one hand and the towering pressure of the Turkish nationalist movement on the other hand pushed them, their Italian counterpart being absent, to grant on 6 May 1919, in a session of the Supreme Council of the Peace Conference, their approval to Greek troops landing in Smyrna with the objective of preserving order and protecting the Christian populations of the region. Thus, on 15 May 1919 the Greek army landed in Smyrna amid a climate of national enthusiasm on the part of native Greeks who thought of the landing as the beginning of liberation.