Raphael Lemkin (1900-1959) was a US jurist and a Jewish Holocaust survivor who served as an adviser to the U.S War Department during WW2. He was the person who invented the concept and the word genocide and was the motivating presence behind the adoption of the United Nations Genocide Convention on December 9, 1948.
While Lemkin dedicated the last 13 years of his life towards making genocide an international crime, his early interest in mass atrocities appears to have originated from the Ottoman Empire's treatment of its non-Turkic minorities.
Lemkin expressed shock when 150 Turkish criminals were set free from the British held island of Malta following WW1. Lemkin wrote:
I was shocked. A nation was killed and the guilty persons were set free.1
While Lemkin first used the term 'genocide' in his 674 page volume titled Axis Rule in Occupied Europe (1944), it's his research on genocide in an unpublished work titled History of Genocide that would relate most to the Greek Genocide. Unfortunately Lemkin died suddenly at the age of 59, and only 20% of the 63 chapter book is found among his comprehensive unpublished scripts. Chapter 5 'Genocide against the Greeks' and Chapter 35 titled 'Smyrna' may have given some insight into Lemkin's thoughts on the Greek Genocide but only survive as an outline and the complete chapters are not found among his papers.
What appears to have survived however is type of 'Background' of 57 pages and a later edited and slightly smaller version of 55 pages titled "Greeks in the Ottoman Empire'. Further information can be found in a study by Dr. Stephen Leonard Jacobs on Lemkin's writings on the Greek, Armenian and Assyrian Genocides in chapter 9 of the publication Genocide in the Ottoman Empire.
In 1946, Lemkin also wrote the following in regards to the massacre of Greeks during WW1 in Ottoman Turkey:
By its very legal, moral and humanitarian nature, it [genocide] must be considered an international crime. The conscience of mankind has been shocked by this type of mass barbarity. There have been many instances of states expressing their concern about another state's treatment of its citizens. The United States rebuked the government of Czarist Russia as well as that of Rumania for the ghastly pogroms they instigated or tolerated. There was also diplomatic action in behalf of the Greeks and Armenians when they were being massacred by the Turks.2
Raphael Lemkin was very much aware of the experience of Greeks within the Ottoman Empire, and his coining of the term 'genocide' was likely a result of his dismay that the perpetrators of the genocide were released, and genocide was repeated later on the Jewish people during WW2. Almost all of Lemkin's family died during the Jewish Holocaust.
Lemkin died alone and in poverty in 1959.
1. Lemkin, Unofficial, quoted in, Shirinian, G. ed. Genocide in the Ottoman Empire: Armenians, Assyrians and Greeks 1913-1923. Berghahn Books 2017, p. 255.
2. American Scholar, Volume 15, no. 2 (April 1946), p. 227-230