Pope Leo XIII is known for his development of the social doctrine of the Church, but few people remember that he used to be called the Pope of the Rosary. In an age “when all evils combine to oppress the Church under their weight”, Leo XIII had recourse to a line of action that had born rich fruits in the past, and exhorted a return to the Holy Rosary of St. Dominic and St. Pius V.
This is why in his encyclical of 1st September 1883 he “decrees and orders that throughout the whole Catholic world the following feast of Our Lady of the Rosary be celebrated with a particular piety and with all the solemnities of the cult: from 1st October to 2nd November at least five decades of the Rosary are to be recited piously in all parish churches followed by the Litanies of Loretto.“ In a declaration of 24th December 1883 the Holy Father expressed his joy that the Catholic people had everywhere been so obedient to his orders. He asked for perseverence in this practice. On 30th August 1884 he renewed for the month of October the prescriptions of the previous year. “Since the attack by the enemies of Christianity is unrelenting, the constancy and energy of the defenders should be no less vigorous…”

On the 20th August 1885 a decree of the Sacred Congregation of Rites ordered that the practice be continued every year as long as this sad state of affairs lasts for the Church and for public affairs.” In the course of the extraordinary jubilee of 1886 the Pope decided to place the jubilee under the patronage of Our Lady of the Rosary. The jubilee year had not ended, with the devotions of the month of the Rosary still in progress, before the Pope wrote to Cardinal Parocchi on the 26th October 1886, his vicar for the city of Rome, that he should establish the daily recitation of the Rosary in the parishes of Rome.
On the 15th August 1889, this time in an encyclical, he inculcated once more in the faithful the necessity of constant prayer to the celestial powers in the combat against the forces of Satan. Having shown in a wonderful fashion the importance of St. Joseph’s titles as patron of the Universal Church, he asked that this great saint be invoked during the month of October at the same time as Mary. This is the reason why a prayer to St. Joseph composed by Leo XIII is recited every day of this month after the Rosary before the Blessed Sacrament.
In short, since 1st September 1883 when the Pope had established by concrete facts the marvellous power of the prayer of the Holy Rosary, he was pleased to insist upon its recitation no less than seven times more. In an encyclical of 22nd September 1891, while changing his method and raising the tone, he considered the Rosary in itself. In magisterial fashion he analysed this Marian devotion and revealed the secret of its incomparable value. He shows how Mary is the Mediatrix in the Economy of Salvation. Our prayers must therefore be addressed to her with confidence, and of all the methods of prayers that there are none is to be preferred to the Holy Rosary: it is such a marvellous composition of meditation and vocal prayer that one would not imagine a method more agreable to the Virgin or more salutary for our souls.
For several years in a row at the approach of the month of October great encyclicals continued to appear on the Rosary. That of 7th September 1892 resumed in a first section the line of teaching begun in the previous encyclical, and went on to develop the idea of the Rosary as a remedy against the corruption of the world, because it is such an easy means of impressing upon the mind the principal dogmas of the Christian faith.
All of his encyclicals on the Holy Rosary would develop this guiding principle, with the exception of the encyclical of 1895 which was concerned to show how the Rosary is a method of achieving the spiritual union of souls.
Leo XIII wrote his last encyclical on the Rosary in 1898, announcing in it his intention to crown his work by a final document, a constitution on the rights and privileges enjoyed by the Confraternities of the Rosary. This apostolic constitution of 2nd October 1898 was followed on 30th August 1899 by the official catalogue of the indulgences of the Rosary. With his Marian work accomplished, Leo XIII gave up his soul to God on the 20th July 1903.