The Roman Pontiffs, and the other Holy Fathers, our predecessors, when they were pressed in upon by temporal or spiritual wars, or troubled by other trials, in order that they might more easily escape from these, and having achieved tranquillity, might quietly and fervently be free to devote themselves to God, were wont to implore the divine assistance, through supplications or Litanies to call forth the support of the saints, and with David to lift up their eyes unto the Mountains, trusting with firm hope that thence would they receive aid.
Prompted by their example, and, as is piously believed, by the Holy Ghost, the inspired Blessed founder of the Order of Friars Preachers, in circumstances similar to those in which we now find ourselves, raised his eyes up unto Heaven, unto that mountain of the Glorious Virgin Mary, loving Mother of God. For she by her seed has crushed the head of the twisted serpent, and has alone destroyed all heresies, and by the blessed fruit of her womb has saved a world condemned by the fall of our first parent.
And so Dominic looked to that simple way of praying and beseeching God, accessible to all and wholly pious, which is called the Rosary, or Psalter of the Blessed Virgin Mary, in which the same most Blessed Virgin is venerated by the angelic greeting repeated one hundred and fifty times, that is, according to the number of the Davidic Psalter, and by the Lord’s Prayer with each decade. Interposed with these prayers are certain meditations showing forth the entire life of Our Lord Jesus Christ, thus completing the method of prayer devised by the Fathers of the Holy Roman Church.
This same method St. Dominic propagated, and it was spread by the Friars of the aforementioned Order, and accepted by not a few of the people. Christ’s faithful, inflamed by these prayers, began immediately to be changed into new men. The darkness of heresy began to be dispelled, and the light of the Catholic Faith to be revealed.
Following the example of our predecessors, seeing that the Church militant, which God has placed in our hands, in these our times is tossed this way and that by so many heresies, and is grievously troubled and afflicted by so many wars, and by the depraved morals of men, we also raise our eyes, weeping but full of hope, unto that same mountain, whence every aid comes forth, and we encourage and admonish each member of Christ’s faithful to do likewise in the Lord.◊
St. Pius V. Consueverunt
Romani Pontifices (excerpts)