Complex sentence: Attending the Second Vatican Council from 1962 to 1965, he succeeded the late Daniel Mannix as Archbishop of Melbourne on 6 November 1963, becoming the first native Australian to hold that office.
Split into simpler sentences: Attending the Second Vatican Council from 1962 to 1965, he succeeded the late Daniel Mannix as Archbishop of Melbourne on 6 November 1963. Simonds was the first native Australian to hold that office.