By the time the Dark Ages were underway in Greece, in the 7th century BC, so was the population which exploded and carried more than half of its share of the Balkan total and over 2,000,000 people in absolute numbers, without mentioning the Greek colonies that had already started being established all over the Eastern Mediterranean, Black sea, Southern Italy, Anatolia and the Adriatic coast.
[3] Hansen's method in calculating the population, is based on the advance and accumulation of archaeological information, both about cities and from surveys of the countryside.
The data collected in the Copenhagen Polis Centre’s Inventory of Archaic and Classical Poleis are also crucial to the Hansen's calculations.
In 1911, just before the Balkan Wars and the Greek Genocide, the Greek population numbered about 8,500,000 (2,701,000 in independent Greece, more than 2,000,000 in the European part of the Ottoman empire and another 3,000,000 in the Asiatic side, with many hundreds of thousands across the Southern Russian empire, Southern Italy, Egypt, Romania, specifically along the Danube, and the Caucasus).
In addition to causing up to 1,1 million deaths (in the civilian population of big cities like Athens and Thessaloniki mostly due to famine and in the countryside mostly due to Italian, Bulgarian and German massacres) and almost wiping out the 70,000 strong Jewish community, the war also left the Greek economy and infrastructure in a deplorable state and caused the 1946-1949 Greek civil war (which was also particularly bloody).
[16] In addition to that, the Greek population under Turkish rule would continue to suffer, first with the Septembriana or Istanbul pogrom.