Complex sentence: The Institute for the Works of Religion, commonly known as the Vatican Bank, was Banco Ambrosiano's main shareholder, and the death of Pope John Paul I in 1978 is rumored to be linked to the Ambrosiano scandal.
Split into simpler sentences: The Institute for the Works of Religion, commonly known as the Vatican Bank, was Banco Ambrosiano's main shareholder. The death of Pope John Paul I in 1978 is rumoured to be linked to the Ambrosiano scandal.