At this proximity of the month of October, which We have already consecrated to the Virgin Mary, under the title of Our Lady of the Rosary, We earnestly exhort the faithful to perform the exercises of this month with, if possible, even more piety and constancy than heretofore. We know that there is sure help in the maternal goodness of the Virgin, and We are very certain that We shall never vainly place Our trust in her.
If, on innumerable occasions, she has displayed her power in aid of the Christian world, why should We doubt that she will now renew the assistance of her power and favour, if humble and constant prayers are offered up on all sides to her? Nay, We rather believe that her intervention will be the more marvellous as she has permitted Us to pray to her, for so long a time, with special appeals.
But We entertain another object: (...) That God may be more favourable to Our prayers, and that He may come with bounty and promptitude to the aid of His Church, We judge it of deep utility for the Christian people, continually to invoke with great piety and trust, together with the Virgin-Mother of God, her chaste Spouse, the Blessed Joseph; and We regard it as most certain that this will be most pleasing to the Virgin herself.
Pope Leo XIII (1810-1903)
Excerpt from his encyclical Quamquam Pluries of August 15, 1889