Complex sentence: He was head of state of Nigeria from 1960 to 1966, serving as the second and last Governor-General from 1960 to 1963 and the first President of Nigeria from 1963 to 1966, holding the presidency throughout the Nigerian First Republic.
Split into simpler sentences: He was head of state of Nigeria from 1963 to 1966. He served as the second and last Governor-General from 1960 to 1963 and the first President of Nigeria from 1963 to 1966, holding the presidency throughout the Nigerian First Republic.