The prolific Leo XIII (1878-1903), known mostly for his encyclicals on social issues, namely “Rerum Novarum” (1891) on the condition of labor, wrote at least 16 documents on the Rosary, including a dozen encyclicals.
This “Rosary Pope” wrote his first encyclical on the rosary in 1883, thus marking the 25th anniversary of the apparitions at Lourdes. In the text he recounts the role of St. Dominic and his preaching of the rosary helped to defeat the Albigensian heretics in southern France in the 12th and 13th centuries.
St. Dominic, the Pope wrote, “proceeded undauntedly to attack the enemies of the Catholic Church, not by force of arms, but trusting wholly to that devotion which he was the first to institute under the name of the Holy Rosary.”
“Guided by divine inspiration and grace,” the Pontiff continued, “he foresaw that this devotion, like a most powerful warlike weapon, would be the means of putting the enemy to flight, and of confounding their audacity and mad impiety.”
He also commented on the “efficacy and power” of the rosary in the historic battle of Lepanto between Christian and Muslim forces in 1521. The Islamic forces had advanced to Spain, and were at the point of overcoming Christendom when Pope Pius V called upon the faithful to pray the rosary. The Christians won, and in honor of this victory, the Pope declared Mary the Lady of Victory and declared her feast day to be held on Oct. 7, the Feast of the Holy Rosary.
Returning to the need for the rosary in his times, the Pope wrote: “It is one of the most painful and grievous sights to see so many souls, redeemed by the blood of Christ, snatched from salvation by the whirlwind of an age of error, precipitated into the abyss of eternal death. Our need of divine help is as great today as when the great Dominic introduced the use of the rosary of Mary as a balm for the wounds of his contemporaries.”