8 That great saint indeed, divinely enlightened, perceived that no remedy would be more adapted to the evils of his time than that men should return to Christ, who "is the way, the truth, and the life," by frequent meditation on the salvation obtained for Us by Him, and should seek the intercession with God of that Virgin, to whom it is given to destroy all heresies. He therefore so composed the Rosary as to recall the mysteries of our salvation in succession, and the subject of meditation is mingled and, as it were, interlaced with the Angelic salutation and with the prayer addressed to God, the Father of Our Lord Jesus Christ. We, who seek a remedy for similar evils, do not doubt therefore that the prayer introduced by that most blessed man with so much advantage to the Catholic world, will have the greatest effect in removing the calamities of our times also. Not only do We earnestly exhort all Christians to give themselves to the recital of the pious devotion of the Rosary publicly, or privately in their own house and family, and that unceasingly, but we also desire that the whole of the month of October in this year should be consecrated to the Holy Queen of the Rosary. We decree and order that in the whole Catholic world, during this year, the devotion of the Rosary shall be solemnly celebrated by special and splendid services. From the first day of next October, therefore, until the second day of the November following, in every parish and, if the ecclesiastical authority deem it opportune and of use, in every chapel dedicated to the Blessed Virgin - let five decades of the Rosary be recited with the addition of the Litany of Loreto. We desire that the people should frequent these pious exercises; and We will that either Mass shall be said at the altar, or that the Blessed Sacrament shall be exposed to the adoration of the faithful, Benediction being afterwards given with the Sacred Host to the pious congregation. We highly approve of the confraternities of the Holy Rosary of the Blessed Virgin going in procession, following ancient custom, through the town, as a public demonstration of their devotion. And in those places where this is not possible, let it be replaced by more assiduous visits to the churches, and let the fervour of piety display itself by a still greater diligence in the exercise of the Christian virtues.
Source: Supremi Apostolatus Officio (Vatican.va)