In 1933 Lemkin made a speech to the Legal Council of the League of Nations conference on international criminal law in Madrid, for which he prepared an essay on the "Crime of Barbarity" as a crime against international law. The purpose of the crime, which later evolved into the idea of genocide, was based mostly on the experience of Assyrians massacred in Iraq on 11 August 1933. The event in Iraq reminded him of earlier similar events of the Armenian Genocide during World War I.