In 1922, after defeat by Turkey and the population exchange which saw 1,250,000 Greeks move across the Aegean (100,000 had departed Eastern Thrace in the decade prior to 1914) the total Greek population was approximately 6,500,000. 250,000 remained in Istanbul. 500-750,000 had been killed during WWI and the Greco-Turkish War of 1922-1923.