Complex sentence: From 1959 to 1968 and again from 1971 to 1996, the duties of the Cabinet Secretary were handed by the Secretary of the Department of the Prime Minister and Cabinet.
Split into simpler sentences: From 1959 to 1968 the duties of the Cabinet Secretary were handed by the Secretary of the Prime Minister's Department. From 1971 to 1996, the duties of the Cabinet Secretary were handed by the Secretary of the Department of the Prime Minister and Cabinet.