From the end of World War I until 1962, New Zealand controlled Samoa as a Class C Mandate under trusteeship through the League of Nations, then through the United Nations. There followed a series of New Zealand administrators who were responsible for two major incidents. In the first incident, approximately one fifth of the Samoan population died in the influenza epidemic of 1918–1919. Between 1919 and 1962, Samoa was administered by the Department of External Affairs, a government department which had been specially created to oversee New Zealand's Island Territories and Samoa. In 1943, this Department was renamed the Department of Island Territories after a separate Department of External Affairs was created to conduct New Zealand's foreign affairs.
What official organization was responsible for Samoa during most of the 20th century?
the Department of External Affairs