At one time a Roman Catholic was to be excommunicated for being a Freemason.
In 1978 newly elected Pope John Paul 'One' was discreetly given a list of 100 Vatican Cardinals and Bishops who were Freemasons.
He intended to excommunicate every one of them the very next day.
33 days into his papacy he was murdered(poisoned) in his bed, buried in the ground and a new pope elected within 12 hours.

The book 'In God's Name' by investigative journalist David Yarrow documents the circumstances surrounding that crime which was the basis for the Godfather *3* movie.