After the Holocaust, which had been perpetrated by the Nazi Germany and its allies prior to and during World War II, Lemkin successfully campaigned for the universal acceptance of international laws defining and forbidding genocides. In 1946, the first session of the United Nations General Assembly adopted a resolution that "affirmed" that genocide was a crime under international law, but did not provide a legal definition of the crime. In 1948, the UN General Assembly adopted the Convention on the Prevention and Punishment of the Crime of Genocide (CPPCG) which defined the crime of genocide for the first time.
Which group convened officially for the first time in 1946?
United Nations General Assembly