Pope Leo XIII may rightly be called The Confraternity Pope given his multiple exhortations to the Church regarding the Confraternity of the Most Holy Rosary.
Excerpt from the 1897 Encyclical of Pope Leo XIII on the Confraternity of the Holy Rosary.
7. We do not hesitate to assign a pre-eminent place among these societies (confraternities) to that known as the Society (Confraternity) of the Holy Rosary.
Excerpt from the 1893 Encyclical of Pope Leo XIII Commending Devotion to the Rosary.
17. It is, therefore, to be desired that renewed zeal should be called forth in the founding, enlarging, and directing of these confraternities, and that not only by the sons of St. Dominic, to whom by virtue of their Order a leading part in this Apostolate belongs, but by all who are charged with the care of souls, and notable in those places in which the Confraternity has not yet been canonically established.
12 Reasons why the MDM has a page devoted to Pope Leo XIII
1. Penned 12 encyclicals and 5 apostolic letters on the Rosary concurrent with the Cape's path to becoming a National Shrine dedicated to Our Lady of the Rosary.
2. Instituted the month of October as the Month of the Rosary. (Paragraph 8)
3. Wrote the Constitution on the Confraternity of the Most Holy Rosary.
4. Landmark encyclical proclaiming the merits of the Confraternity.
5. Consecrated the World to the Sacred Heart of Jesus.
6. Encyclical on Devotion to St. Joseph including Prayer to St. Joseph.
7. Encyclical on the Holy Spirit - On January 1st 1901 Pope Leo XIII prayed the "Veni Creator Spiritus" and consecrated the 20th Century to the Holy Spirit - the Charismatic renewal began around the same time.
8. Granted a plenary indulgence to those who make St. Louis de Montfort's Act of Consecration of the Blessed Virgin.
9. Beatified St. Louis de Montfort in 1888, the same year the Cape was dedicated to Our Lady of the Rosary and the event of the Prodigy of the Eyes.
10. Pope Leo XIII prescribed what became known as the Leonine prayers including the St. Michael prayer, Salve Regina and three Ave Maria's to be recited after low mass.
11. Pope Leo XIII established the Archconfraternity of the Holy Face on October 1st, 1885.
12. Penned an encyclical on the Holy Eucharist on the Vigil of the Solemnity of Corpus Christi in 1902.