Perhaps one of the greatest embarrassments to the Roman Catholic Church was Pope Alexander VI. The Pope kept his mistress in the Vatican. Now first of all there was an issue of him having the mistress. Second of all what’s he doing breaking the vow of celibacy?
He voted his son Cesare to the Cardinals. Which is interesting because it is the Cardinals who vote on who the Pope will be. Cardinal Cesare died from syphilis and his daughter was the known person to poison whatever guest where not considered trustworthy.