Complex sentence: He served as the Chief Minister of Grenada from 1960 until 1961 and from 1962 until 1967, and later as Prime Minister of Grenada from 1984 until his death.
Split into simpler sentences: He served as the Chief Minister of Grenada from 1960-61, and again, from 1962-67. Later he served as Prime Minister of Grenada from 1984 until his death.