The death sentence is a necessary and efficacious means for the Church to attain its end when rebels act against it and disturbers of the ecclesiastical unity, especially obstinate heretics and heresiarchs, cannot be restrained by any other penalty from continuing to derange the ecclesiastical order and impelling others to all sorts of crime ... When the perversity of one or several is calculated to bring about the ruin of many of its children it is bound effectively to remove it, in such wise that if there be no other remedy for saving its people it can and must put these wicked men to death.
Pope Leo XIIIIt must be assumed and established as a principle, that the right of private property must be regarded as sacred. Wherefore, the law ought to favor this right and, so far as it can, see that the largest possible number among the masses of the population prefer to own property.... But if the productive activity of the multitude can be stimulated by the hope of acquiring some property... , it will gradually come to pass that, with the difference between extreme wealth and extreme penury removed, one class will become the neighbor to the other.
Pope Leo XIIIThe empire of Christ the King includes not only Catholic nations, not only baptized persons who, though of right belonging to the Church, have been led astray by error, or have been cut off from her by schism, but also all those who are outside the Christian faith: so that truly the whole of mankind is subject to the power of Jesus Christ.
Pope Leo XIIIIt is not the part of prudence to neglect that which antiquity in its long experience has approved and which is also taught by apostolic authority.
Pope Leo XIII