The heretics have made their false theology popular and presented it in a way that is within the capacity of the common people. They preach it to the people and teach it in the schools, and scatter pamphlets that can be bought and understood by many; they influence people by their writings when they cannot reach them by preaching. Their success is largely due to the negligence of those who should have shown some interest, and the bad example and the ignorance of Catholics, especially the clergy, have made such ravages in the vineyard of the Lord.
--St. Ignatius Loyola, Letter to St. Peter Canisius