Encyclical of Pope Pius XII Ingruentium Malorum on reciting the Rosary

12. But it is above all in the bosom of the family that We desire the custom of the Holy Rosary to be everywhere adopted, religiously preserved, and ever more intensely practiced. In vain is a remedy sought for the wavering fate of civil life, if the family, the principle and foundation of the human community, is not fashioned after the pattern of the Gospel.
13. To undertake such a difficult duty, We affirm that the custom of the family recitation of the Holy Rosary is a most efficacious means. What a sweet sight - most pleasing to God - when, at eventide, the Christian home resounds with the frequent repetition of praises in honor of the august Queen of Heaven! Then the Rosary, recited in common, assembles before the image of the Virgin, in an admirable union of hearts, the parents and their children, who come back from their daily work. It unites them piously with those absent and those dead. It links all more tightly in a sweet bond of love, with the most Holy Virgin, who, like a loving mother, in the circle of her children, will be there bestowing upon them an abundance of the gifts of concord and family peace.

14. Then the home of the Christian family, like that of Nazareth, will become an earthly abode of sanctity, and, so to speak, a sacred temple, where the Holy Rosary will not only be the particular prayer which every day rises to heaven in an odor of sweetness, but will also form the most efficacious school of Christian discipline and Christian virtue. This meditation on the Divine Mysteries of the Redemption will teach the adults to live, admiring daily the shining examples of Jesus and Mary, and to draw from these examples comfort in adversity, striving towards those heavenly treasures "where neither thief draws near, nor moth destroys" (Luke 12, 33). This meditation will bring to the knowledge of the little ones the main truths of the Christian Faith, making love for the Redeemer blossom almost spontaneously in their innocent hearts, while, seeing, their parents kneeling before the majesty of God, they will learn from their very early years how great before the throne of God is the value of prayers said in common.
15. We do not hesitate to affirm again publicly that We put great confidence in the Holy Rosary for the healing of evils which afflict our times. Not with force, not with arms, not with human power, but with Divine help obtained through the means of this prayer, strong like David with his sling, the Church undaunted shall be able to confront the infernal enemy, repeating to him the words of the young shepherd: "Thou comest to me with a sword, and a spear, and with a shield; but I come to thee in the name of the Lord of Hosts, the God of armies . . . and all this assembly shall know that the Lord saveth not with sword and spear, for this is his battle, and he will deliver you into our hands" (I Kings 17, 45-47).

The Battle of Lepanto and the development of devotion towards the Holy Rosary

The sixteenth century was marked by the expansion of the Ottoman Empire.  The Turks, who already occupied most of the Mediterranean, Northern Africa, the Middle East and the Balkanic Peninsula, were threatening Western Europe.  They took Belgrade in 1521, held Rhodes the following year, and then invaded Hungary and sieged Vienna in 1529.  They were driven back by a tiny margin and run aground at Malta, retreating to take Cyprus, a then Venitian possession.
Faced with the Turkish threat, Europe did not combine forces well.  France even maintained friendly relations with Constantinople.  Under such unvafourable circumstances, Pope St Pius V patiently but persistently endeavoured to form a coalition against the Turks amongst the various European kingdoms.  Ha finally managed to establish an alliance with Spain, Venice and Malta.  In May 1571, St Pius V solemnly proclaimed from St Peter's Basilica the establishment of the Holy League.  An impressive fleet was formed, entrusted to Don Juan of Austria, the brother of King Philip II of Spain.  To beseech heavenly protection over the fleet, St Pius V ordered a solemn jubilee together with fasting and the public recitation of the Rosary.
The decisive battle took place on October 7, 1571 in the golf of Lepanto, outside the isthmus of Corinth.  It involved 213 venitian and spanish galleys et some 300 turkish galleys.  Approximately 100,000 men fought on each side.  The Christian fleet won a full victory, due to the heavy artillery that had been taken on board.  Almost all enemy galleys were either taken or sunken.  Turkish Admiral Ali Pacha was made prisoner and beheaded.  Fifteen thousand christian prisoners were freed.  Barely one third of the Turkish fleet managed to get away, thus sweeping away the legend of invincibility of the Turkish fleet.
On the very evening of the battle, Pope St Pius V suddenly left his desk for the window, where he appeared to contemplate a vision.  Then he turned to the surronding prelates and said: "Let us give thanks to God: our army is victorious".  It was October 7 shortly before 5 p.m., that very hour at which Don Juan, victorious, knelt on the bridge of his ship to thank God for His protection.  The news of victory did not reach Rome until October 26, 19 days later, thus confirming the revelation granted to the Holy Father.
In memory of the battle of Lepanto, Pius V added the following invocation to the litanies of the Blessed Virgin Mary: "Help of Christians, pray for us", and ordained the institution of the Feast of Our Lady of Victories, which Pope Gregory XIII then established as the Feast of the Rosary in all churches each first Sunday in October.
Throughout the catholic people the victory of Lepanto soon contibuted to the rapid expansion of devotion towards the Rosary et gave rise to the creation of many confraternities.  It remains a key date in the history of Marian devotion.