In a letter of September 1, 1883, mindful of the Rosary's power to strengthen faith and foster a life of virtue, he outlined the triumphs of the Rosary in past times and admonished the faithful to dedicate the month of October to the Blessed Virgin through the daily recitation of her Rosary in the presence of the Blessed Sacrament, in order to obtain through her intercession the grace that God would console and defend His Church in her sufferings.Beginning on September 1, 1883, with SUPREMO APOSTOLATUS OFFICIO, Pope Leo wrote a total of eleven encyclicals on the Rosary, ending with DIUTURNI TEMPORIS in 1898. (Source: Rev. Matthew R. Mauriello, Catholic.net).
The spread of the devotion of the rosary is attributed to the revelation of Mary to St. Dominic, who sought her help in battling the heresy of the Albigenses. Robert Feeney's "St. Dominic and the Rosary" gives a detailed account, asserting that "the tradition that Mary first revealed the Rosary devotion to St. Dominic is supported by 13 popes":
St. Dominic went into the villages of the heretics, gathered the people, and preached to them the mysteries of salvation - the Incarnation, the Redemption, Eternal Life. As the Holy Virgin had taught him to do, he distinguished the different kinds of mysteries and after each short instruction he had ten Hail Marys recited. St. Dominic found great success in this new devotion, bringing about the conversion of the Albigensians.
The late Dominican Reginald Garrigou-Lagrange has stated: "Our Blessed Lady made known to St. Dominic a kind of preaching till then unknown; which she said would be one of the most powerful weapons against future errors and in future difficulties." However, authors Herbert Thurston and Andrew Shipman in the 1917 Catholic Enyclopedia see reasonable cause to dispute this claim, noting that "the practice of repeating a hundred and fifty Aves" pre-date St. Dominic, as well as the dearth of "any satisfactory evidence to show that St. Dominic had identified himself with the pre-existing Rosary and become its apostle." They conclude:
No doubt can exist that the immense diffusion of the Rosary and its confraternities in modern times and the vast influence it has exercised for good are mainly due to the labours and the prayers of the sons of St. Dominic, but the historical evidence serves plainly to show that their interest in the subject was only awakened in the last years of the fifteenth century.
Whatever the mystery (and continued debate) of its historical origins, the Rosary is commended to the faithful by numerous popes and saints of the Church --it was heralded as "my favorite prayer! a marvellous prayer!" by Pope John Paul II, praising its "simplicity and its depth" (See: Rosarium Virginis Mariae - "On the Most Holy Rosary" October 2002).
More recently, in an address at the Basilica of St. Mary Major in 2008, Pope Benedict XVI summarized its benefits thus:
... the Holy Rosary is not a pious practice banished to the past, like prayers of other times thought of with nostalgia. Instead, the Rosary is experiencing a new Springtime. Without a doubt, this is one of the most eloquent signs of love that the young generation nourish for Jesus and his Mother, Mary. In the current world, so dispersive, this prayer helps to put Christ at the centre, as the Virgin did, who meditated within all that was said about her Son, and also what he did and said. When reciting the Rosary, the important and meaningful moments of salvation history are relived. The various steps of Christ's mission are traced. With Mary the heart is oriented toward the mystery of Jesus. Christ is put at the centre of our life, of our time, of our city, through the contemplation and meditation of his holy mysteries of joy, light, sorrow and glory. May Mary help us to welcome within ourselves the grace emanating from these mysteries, so that through us we can "water" society, beginning with our daily relationships, and purifying them from so many negative forces, thus opening them to the newness of God. The Rosary, when it is prayed in an authentic way, not mechanical and superficial but profoundly, it brings, in fact, peace and reconciliation. It contains within itself the healing power of the Most Holy Name of Jesus, invoked with faith and love at the centre of each "Hail Mary".
Urged by his campaign manager to make no mention of religion, Belloc began his first election speech in typical pugnacious fashion: “Gentlemen, I am a Catholic. As far as possible, I go to Mass every day. This (taking a rosary out of his pocket) is a rosary. As far as possible, I kneel down and tell these beads every day. If you reject me on account of my religion, I shall thank God that He has spared me the indignity of being your representative.”
After a shocked silence, there was applause. Belloc won.