Greek forces landed at Smyrna (İzmir) with Allied backing, opening a new phase of fighting in western Anatolia after World War I. The campaign escalated violence and displacement among local communities. These events set the conditions for later negotiations that tried to “solve” minority issues through forced population transfer.
The Treaty of Neuilly (Bulgaria–Allies) changed borders in the Balkans and intensified debates about minorities and “reciprocal” migration. It is part of the wider postwar diplomacy that treated population transfer as a tool for stabilizing new states. This context helped make compulsory exchange between Greece and Turkey politically thinkable a few years later.
After Turkish forces entered Smyrna, a major fire (13–22 September 1922) destroyed large parts of the city and produced a surge of refugees. The catastrophe deepened the humanitarian crisis and hardened political positions on both sides. It also made the question of how to deal with displaced Orthodox Christians and Muslims more urgent.
The Armistice of Mudanya set terms for ending hostilities and arranging withdrawals in Eastern Thrace, while a final peace was negotiated. It marked a shift from battlefield outcomes to diplomatic settlement. These talks soon moved to Lausanne, where the population exchange was formalized.
Diplomatic negotiations opened at Lausanne to settle borders, sovereignty, and minority issues after the war. Delegates also debated how to address violence and displacement that had already occurred. The conference produced both a peace treaty and the separate convention ordering a compulsory population exchange.
Greece and Turkey signed the Convention Concerning the Exchange of Greek and Turkish Populations, making the transfers compulsory and tying “who must move” mainly to religion (Greek Orthodox vs. Muslim). It also set up procedures for property and for an international Mixed Commission to supervise execution. The convention became a central instrument for creating more religiously homogeneous nation-states.
Article 2 of the convention exempted the Greek inhabitants of Constantinople (Istanbul) and the Muslim inhabitants of Western Thrace from the compulsory exchange. Disputes soon arose over what it meant to be “established” in these places and who qualified for exemption. These definitions mattered because they determined who could legally remain and who was forced to leave.
The Treaty of Lausanne set the international recognition and borders of the new Republic of Turkey and incorporated related conventions, including the exchange agreement. It turned wartime displacement into a formal, internationally backed program. The treaty framework also created ongoing legal and administrative work around property, compensation, and minority protections.
Turkey ratified the exchange convention on 23 August 1923, and Greece ratified it on 25 August 1923. Ratification gave the convention legal force and enabled full-scale implementation under the Lausanne system. This step helped shift the exchange from a negotiated plan into an enforceable state policy.
On League of Nations initiative, the Refugee Settlement Commission was established to support relief and longer-term rehabilitation of refugees in Greece. It relied heavily on “exchangeable” properties left by departing Muslims, along with other land and assets, to build housing and support agricultural resettlement. This institution became one of the main tools for implementing the exchange on the Greek side.
The Treaty of Lausanne became effective after ratifications were deposited, bringing the broader peace settlement fully into force. By this stage, most of the compulsory transfers had already occurred, but the treaty’s legal machinery continued to matter for property claims and minority status. It also reinforced the post-Ottoman shift toward nation-states with sharply reduced minority populations.
The exchange convention was registered in the League of Nations Treaty Series, reflecting its standing as an international agreement. Registration helped document the legal basis for ongoing work by international and mixed bodies dealing with implementation and disputes. It also shows how the exchange was treated as part of the interwar international legal order, not just a bilateral act.
Because Greece and Turkey disagreed about who counted as “established” (and therefore exempt) under Article 2, the question was sent for an advisory opinion to the Permanent Court of International Justice (PCIJ). The PCIJ’s opinion clarified how to interpret the exemption language and emphasized that the convention’s criteria were meant to distinguish exchangeable from non-exchangeable populations. This ruling shaped how the exemptions were applied in practice.
Greece and Turkey signed a further agreement to manage unresolved issues from the exchange, especially disputes over property, compensation, and legal status. The agreement provided for arbitration mechanisms that could address cases the earlier commission process could not settle. This marked a transition from mass movement to long-term legal cleanup of the exchange’s consequences.
The 1923 Greek–Turkish Population Exchange and its implementation (1919–1926)