18 All of you know their purpose, subterfuges, and methods. On Our part We have denounced and condemned their scheming. They are proposing a universal apostasy even worse than the one that threatened the age of Charles. It is worse, We say, because it stealthily creeps into the very veins of the Church, hides there, and cunningly pushes erroneous principles to their ultimate conclusions.
Source: Editae Saepe (Vatican.va)