Hence from all we have hitherto said, it is clear beloved Catholics that we cannot approve the opinions which some [Protestants, Jews, and other heretics] comprise under the head of Americanism [freedom].
Pope Leo XIIIBut the supreme teacher in the Church is the Roman Pontiff. Union of minds, therefore, requires, together with a perfect accord in the one faith, complete submission and obedience of will to the Church and to the Roman Pontiff, as to God Himself.
Pope Leo XIIIEvery man has by nature the right to possess property as his own. This is one of the chief points of distinction between man and the animal creation.
Pope Leo XIIINot only, in strict truth, was marriage instituted for the propagation of the human race, but also that the lives of husbands and wives might be made better and happier.
Pope Leo XIII