From the Brevarium Romanum for the feast of the Holy Rosary of the Blessed Virgin Mary

When the heresy of the Albigenses was making head against God in the County of Toulouse, and striking deeper roots every day, the holy Dominick, who had but just laid the foundations of the Order of Friars Preachers, threw his whole strength into the travail of plucking these blasphemies up. That he might be fitter for the work, he cried for help with his whole soul to that Blessed Maiden, whose glory the falsehoods of the heretics so insolently assailed, and to whom it hath been granted to trample down every heresy throughout the whole earth. It is said that he had from her a word, bidding him preach up the saying of the Rosary among the people, as a strong help against heresy and sin, and it is wonderful with how stout an heart and how good a success he did the work laid upon him. This Rose-garden (or Rosary) is a certain form of prayer, wherein we say onehundred-and-fifty times the salutation of the Angel, and the Lord's Prayer between every ten times, and, each of the fifteen times that we say the Lord's Prayer, and repeat tenfold the salutation, think of one of fifteen great events in the history of our Redemption. From that time forth this form of godly prayer was extraordinarily spread about by holy Dominick, and waxed common. That this same Dominick was the founder and prime mover thereof hath been said by Popes in divers letters of the Apostolic See.

From this healthy exercise have grown up numberless good fruits in the Christian Commonwealth. Among these deserveth well to be named that great victory over the Sultan of Turkey, which the most holy Pope Pius V., and the Christian Princes whom he had roused, won at Lepanto, (on the th day of October, the first Lord's Day in the month, in the year of our Lord 1571) The day whereon this victory was gained was the very one whereon the Guildbrethren of the most holy Rosary, throughout the whole world, were used to offer their accustomed prayers and appointed supplications, and the event therefore was not unnaturally connected therewith. This being the avowed opinion of Gregory XIII., he ordered that in all Churches where there was, or should be, an Altar of the Rosary, a Feast, in the form of a Greater Double, should be kept for ever upon the first Lord's Day of the month of October, to give unceasing thanks to the Blessed Virgin, under her style of (Queen of) the (Most Holy) Rosary, for that extraordinary mercy of God. Other Popes also have granted almost numberless Indulgences to those who say the Rosary, and to those who join its Guilds.

In the year 1716, Charles VI., Elect- Emperor of the Romans, won a famous victory over countless hordes of Turks, near Temeswar, in the kingdom of Hungary, upon the day when the Feast of the Dedication of the Church of St Mary of the Snows was being kept, and almost at the very moment when the Guildbrethren of the most holy Rosary were moving through the streets of Rome in public and solemn procession, amid vast multitudes, all filled with the deepest enthusiasm, calling vehemently upon God for the defeat of the Turks, and entreating the Virgin Mother of God to bring the might of her succour to the help of the Christians. A few days later, (upon the Octave of the Feast of the Assumption,) the Turks raised the siege of Corfu. These mercies Clement XI. devoutly ascribed to the helpful prayers of the Blessed Virgin, and that the memory and the sweetness of such a blessing might for all time coming endure gloriously, he extended to the whole Church the observance of the Feast of the most holy Rosary, for the same day and of the same rank, (as it had already been in the places before mentioned.) Benedict XIII. commanded the record of all these things to be given a place in the Service-book of the Church of Rome; and Leo XIII., in the most troublous times of the Church and the cruel storm of long pressing evils, by fresh Apostolic letters vehemently urged upon all the faithful throughout the earth the often saying of the Rosary of (the Blessed Virgin) Mary, raised the dignity of the yearly festival, added to the Litany of Loretto the Invocation Queen of the Most Holy Rosary, and granted to the whole Church a special Office for this solemn occasion. Let us all then be earnest in honouring the most holy Mother of God in this form which she liketh so well, that even as the entreaties of Christ's faithful people, approaching her in her Garden of Roses, have so often won her to scatter and destroy their earthly foes, so she may gain for them the victory over their hellish foes likewise.