Saint Pius V (1566-1572) is the pope of the Rosary of Lepanto. His three Marian documents in Doctrina Pontificia IV (nn. 168-170) constitute the great sixteenth-century legislation on the Rosary, in the midst of the Counter-Reformation. It is Saint Pius V who fixes the Rosary in its form of 15 mysteries, which endured until John Paul II added the Luminous Mysteries in 2002.

Collection	Doctrina Pontificia IV: Marian Documents, nn. 168-170
Pope	Saint Pius V (1566-1572)
Documents	Ex omnibus afflictionibus (1567) \| Consueverunt RR. PP. (1569) \| Super speculam (1570)
Topic	Rosary, Battle of Lepanto, Our Lady of Victory

n. 168, bull “Ex omnibus afflictionibus” (October 1, 1567)

This bull condemns seventy-nine propositions of Michael Baius on grace, original sin, and redemption. Its Marian relevance is that, in condemning Baius’s avant la lettre Jansenism, Pius V protects the doctrine of Mary’s special grace, including her preservation from original sin, which Baius called into question.

n. 169, constitution “Consueverunt Romani Pontifices” (September 17, 1569)

This is the magna carta of the Rosary: the first papal document that systematically describes the history, the structure, and the spiritual benefits of the Rosary. Pius V attributes the origin of the Rosary to Saint Dominic (an attribution today historically contested, but piously upheld) and fixes the 15 mysteries: 5 joyful, 5 sorrowful, 5 glorious.

«Consueverunt Romani Pontifices, pro suo pastorali officio… laudare et approbare eas pietatis exercitationes, quae ad animarum salutem et Dei cultum proficere comperiuntur. Inter quas, hoc Rosarium sive Psalterium Beatae Mariae Virginis…».
The Roman Pontiffs, by their pastoral office, are accustomed to praise and approve those exercises of piety which are found to be profitable to the salvation of souls and to the worship of God. Among them, this Rosary or Psalter of the Blessed Virgin Mary…

The Battle of Lepanto (October 7, 1571)

Pius V ordered the Rosary to be prayed throughout Christendom while the fleet of the Holy League fought the Ottoman fleet in the Gulf of Lepanto. The Christian victory on October 7, 1571, was attributed by Pius V to the intercession of Our Lady of the Rosary. He instituted the feast of “Our Lady of Victory” (later called “Our Lady of the Rosary”) on October 7, which is the dies natalis of the Mariology of the Rosary as a spiritual weapon of the Church.

n. 170, constitution “Super speculam domini” (November 30, 1570)

This document on the reform of the liturgical calendar includes provisions on the Marian feasts, confirming Mary’s place in the calendar of the Church reformed by the Council of Trent.