According to legend, the rosary was given to St. Dominic by Mary herself, around the year 1200, and was used to defeat the Albigensian heresy. In reality, it was centuries before Dominic that illiterate lay brothers, who could not recite the 150 psalms prayed by the monks, said 150 Our Fathers in their place. By the twelfth century, Hail Marys were said in place of Our Fathers, and strings of beads were made to keep track of these prayers. The name "rosary" came from an early legend, according to which Our Lady took roses from the lips of a monk while he was praying the rosary, and weaved it into a garland, which she placed on her head.
The rosary begins on the crucifix, where the Apostles Creed is recited. On the first large bead, the Our Father is prayed. On the three small beads, Hail Marys are said. The Glory Be is recited on the second large bead. The remainder of the rosary consists of five decades (series of ten small beads). Each decade begins on a large bead, on which is prayed the Our Father. On the ten small beads, ten Hail Marys are said. In conclusion, on the large bead, the Glory Be is prayed. It is a popular custom to add the Fatima prayer after the Glory Be, revealed for that purpose to the shepherd children during the apparitions there in 1916-17. On the completion of the rosary, the Hail Holy Queen is recited. When praying publically in church, an Our Father and a Hail Mary should be recited for the pope's intentions, in order to gain the plenary indulgence. Rosaries recited privately are given a partial indulgence.
But rather than meditating on the words of the rosary prayers, one must meditate instead on the mysteries of the rosary. The rosary is both vocal and mental. The prayers are the "body" of the rosary, and are simply used to measure a length of time in which to dwell upon one of the mysteries. The meditations are the "soul" of the rosary. The main purpose of the rosary is to meditate upon aspects of Christ's life. These meditations come in three sets of five decades: the Joyful Mysteries–the Annunciation (Luke 1:26-38), the Visitation (Luke 1:40-55), the Nativity (Luke 2:6-20), the Presentation (Luke 2:21-39), and the Finding in the Temple (Luke 2:41-51); the Sorrowful Mysteries–the Agony in the Garden (Matt. 26:36-46), the Scourging (Matt. 27:26), the Crowing with Thorns (Matt. 27:29), the Carrying of the Cross (Luke 23:26-32), and the Crucifixion (Luke 23:33-46); the Glorious Mysteries–the Resurrection (Luke 24:1-12), the Ascension (Luke 24:50-51), the Descent of the Holy Spirit (Acts 2:1-4), the Assumption, and the Coronation. These mysteries took on their present form and were popularized through the preaching of Dominican Blessed Alan de la Roche (d. 1475).
A good method of praying the rosary is to use the Apostles Creed to meditate upon any intentions that one would like to offer up through the rosary. The first Our Father may be prayed for the general intention of the Catholic Church, the three Hail Marys for the increase in faith, hope and charity, and the first Glory Be for the Holy Father. On each decade, an intention may be offered through the intercession of a chosen saint, and meditated upon during the Our Father, while the Hail Marys are used to meditate upon the mystery. Depending on one's preference, it may be a good practice to obtain and use a rosary prayer book containing a series of meditations on which to use while praying each decade. One of the most popular forms of this method is the Scriptural Rosary, which contains ten excerpts from Scripture to be used in recitation and meditation. One may meditate on some or all of the passages.
Why should we pray the daily rosary? The rosary is the greatest and most efficacious prayer outside of the Mass. Francis de Sales called the rosary the greatest method of praying. The rosary has been called by popes everything from "the scourge of the devil" (Adrian VI) to a "treasure of graces" (Paul V). Padre Pio called it "the weapon", and Pope John XXIII prayed the entire 15-decade rosary daily.
Besides this, Mary made 15 promises to Christians who recite the rosary: 1. Whoever shall faithfully serve me by the recitation of the rosary, shall receive signal graces. 2. I promise my special protection and the greatest graces to all those who shall recite the rosary. 3. The rosary shall be a powerful armor against hell, it will destroy vice, decrease sin, and defeat heresies. 4. It will cause virtue and good works to flourish; it will obtain for souls the abundant mercy of God; it will withdraw the hearts of men from the love of the world and its vanities, and will lift them to the desire of eternal things. Oh, that souls would sanctify themselves by this means. 5. The soul which recommends itself to me by the recitation of the rosary, shall not perish. 6. Whoever shall recite the rosary devoutly, applying himself to the consideration of its sacred mysteries shall never be conquered by misfortune. God will not chastise him in His justice, he shall not perish by an unprovided death; if he be just he shall remain in the grace of God, and become worthy of eternal life. 7. Whoever shall have a true devotion for the rosary shall not die without the sacraments of the Church. 8. Those who are faithful to recite the rosary shall have during their life and at their death the light of God and the plentitude of His graces; at the moment of death they shall participate in the merits of the saints in paradise. 9. I shall deliver from purgatory those who have been devoted to the rosary. 10. The faithful children of the rosary shall merit a high degree of glory in Heaven. 11. You shall obtain all you ask of me by the recitation of the rosary. 12. All those who propagate the holy rosary shall be aided by me in their necessities. 13. I have obtained from my Divine Son that all the advocates of the rosary shall have for intercessors the entire celestial court during their life and at the hour of death. 14. All who recite the rosary are my sons, and brothers of my only son Jesus Christ. 15. Devotion to my rosary is a great sign of predestination.