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 Blessed Dominic, namely, 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. Sodalities for this form of prayer began to be instituted in many places by the Friars of the same Order, legitimately deputed to this work by their Superiors, and confreres began to be enrolled together.
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 deprave 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.
Given at Rome at St. Peter’s, under the Fisherman’s ring, 17 September 1569, in the fourth year of our Pontificate.
Pope Saint Pius V, Consueverunt Romani Pontifices