10 These things being so, then, venerable brethren, as at the beginning of Our pontificate We, on whom the guidance of the whole Church now lies, pointed out a place of refuge to the peoples and the princes tossed about by the fury of the tempest, so now, moved by the extreme peril that is on them, We again lift up Our voice, and beseech them again and again for their own safety's sake as well as that of their people to welcome and give ear to the Church which has had such wonderful influence on the public prosperity of kingdoms, and to recognize that political and religious affairs are so closely united that what is taken from the spiritual weakens the loyalty of subjects and the majesty of the government. And since they know that the Church of Christ has such power to ward off the plague of socialism as cannot be found in human laws, in the mandates of magistrates, or in the force of armies, let them restore that Church to the condition and liberty in which she may exert her healing force for the benefit of all society.
Source: Quod Apostolici Muneris (Vatican.va)