“20. …[some] desire vehemently to separate the Church from the state, and to break the mutual concord between temporal authority and the priesthood. It is certain that that concord which always was favorable and beneficial for the sacred and the civil order is feared by the shameless lovers of liberty. 
21. But for the other painful causes We are concerned about, you should recall that certain societies and assemblages seem to draw up a battle line together with the followers of every false religion and cult. They feign piety for religion; but they are driven by a passion for promoting novelties and sedition everywhere. They preach liberty of every sort; they stir up disturbances in sacred and civil affairs, and pluck authority to pieces.
22. We write these things to you with grieving mind but trusting in Him who commands the winds and makes them still. Take up the shield of faith and fight the battles of the Lord vigorously. You especially must stand as a wall against every height which raises itself against the knowledge of God. Unsheath the sword of the spirit, which is the word of God, and may those who hunger after justice receive bread from you. Having been called so that you might be diligent cultivators in the vineyard of the Lord, do this one thing, and labor in it together, so that every root of bitterness may be removed from your field, all seeds of vice destroyed, and a happy crop of virtues may take root and grow. The first to be embraced with paternal affection are those who apply themselves to the sacred sciences and to philosophical studies. For them may you be exhorter and supporter, lest trusting only in their own talents and strength, they may imprudently wander away from the path of truth onto the road of the impious. Let them remember that God is the guide to wisdom and the director of the wise.[31] It is impossible to know God without God who teaches men to know Himself by His word.[32] It is the proud, or rather foolish, men who examine the mysteries of faith which surpass all understanding with the faculties of the human mind, and rely on human reason which by the condition of man's nature, is weak and infirm.”  Pope Gregory XVI, Mirari Vos, August 15, 1832