Quanta Cura, Pius IX 1864.

For which cause the same Our Predecessors, have, with Apostolic fortitude, constantly resisted the nefarious enterprises of wicked men, who, like raging waves of the sea foaming out their own confusion, and promising liberty whereas they are the slaves of corruption, have striven by their deceptive opinions and most pernicious writings to raze the foundations of the Catholic religion and of civil society, to remove from among men all virtue and justice, to deprave persons, and especially inexperienced youth, to lead it into the snares of error, and at length to tear it from the bosom of the Catholic Church.

Mirari Vos, Gregory XVI 1832

Here We must include that harmful and never sufficiently denounced freedom to publish any writings whatever and disseminate them to the people, which some dare to demand and promote with so great a clamor. We are horrified to see what monstrous doctrines and prodigious errors are disseminated far and wide in countless books, pamphlets, and other writings which, though small in weight, are very great in malice. We are in tears at the abuse which proceeds from them over the face of the earth. Some are so carried away that they contentiously assert that the flock of errors arising from them is sufficiently compensated by the publication of some book which defends religion and truth. Every law condemns deliberately doing evil simply because there is some hope that good may result. Is there any sane man who would say poison ought to be distributed, sold publicly, stored, and even drunk because some antidote is available and those who use it may be snatched from death again and again?