Origins of the rosaries
The first description of a practice that resembles the modern rosary prayer has be found in the Meditations on the Joys of the Blessed Virgin of the Cistercian Stephen of Sallay (died 1252) who worked out an exercise of prayer for 15 Marian "joys" divided into 3 sections. While the number 15 and the joys connect the writing to the Rosary, the complexity and length are different. More important for the spirit of the Rosary were the "Meditations on the Life of Christ" that from the beginning of 1300 were attributed to St Bonaventure. The meditations on the public life of Christ begin with his Baptism and end with the Last and they are attentive to the presence of Mary. Even more determining for the Rosary was the Life of Jesus Christ compiled from the four Gospels and orthodox authors of Life of Christ of Ludolph of Saxony (died 1377) published in Strasbourg in 1474 and reprinted soon after in 88 Latin editions. The author was first a Dominican and then a Carthusian, who drafted a comprehensive outline, with quotations from the Fathers and medieval authors, with a prayer concluding each chapter. He contributed to integrating the use of set mysteries of Christ in personal prayer.
The division of the Psalter into 150 Hail Mary's spread over 15 decades, each one preceded by an Our Father is attributed to the Carthusian Henry Egher of Kalcar (died 1408). The definitive contribution was that of the Breton Dominican Alan de la Roche (died 1475), who established the Rosary as a pastoral tool. He proposed a "prayer directly addressed to Christ. So the first fifty are prayed to honor Christ, Incarnate Word. The second, Christ who suffered the Passion. The third, in honor of Christ who rose, ascended into heaven, who sent the Paraclete, who sits at the right hand of the Father, who will come to judge". Alan de la Roche gave preference to the 3 sets and the 15 decades. He also provided a theoretical foundation to the Psalter of the Virgin Mary discovering it in the prayer of the monks, the Fathers, the Apostles and the Blessed Virgin Mary herself, who entrusted it especially to St Dominic.
In 1521 at Venice, Alberto Castellani published the Rosary of the glorious Virgin Mary maintaining the 150 phrases, but connected the meditation to the Our Father and calling it a mystery and so favoring the present format. The modern format of the rosary was first described by St Pius V in the Bull Consueverunt (17 September 1569), where one reads that "the Rosary or Psalter of the Blessed Virgin" is a "method of prayer" through which we "venerate Mary with the Angelic salutation repeated 150 times according to the number of David's psalms, and before every set of ten Hail Mary's we say the prayer of Our Lord with meditations that illustrate the entire life of the same Lord Jesus Christ."