Pope Leo XIII personally started the practice of devoting October to the Rosary devotion. 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.
Queen of the most holy Rosary, in these times of such brazen impiety, manifest thy power with the signs of thine ancient victories, and from thy throne, whence thou dost dispense pardon and graces, mercifully regard the Church of thy Son, His Vicar on earth, and every order of clergy and laity, who are sore oppressed in the mighty conflict. Do thou, who art the powerful vanquisher of all heresies, hasten the hour of mercy, even though the hour of God’s justice is every day provoked by the countless sins of men. For me who am the least of men, kneeling before thee in supplication, do thou obtain, the grace I need to live righteously upon earth and to reign. among the just in heaven, the while in company with all faithful Christians throughout the world, I salute thee and acclaim thee as Queen of the most holy Rosary:
Queen of the most holy Rosary, pray for us.