The Rosary – in Pope Paul VI’s felicitous phrase – is “a compendium of the Gospel.” Indeed, it is a brief summary of the Life of Christ in the manner of St. Peter’s discourse in the house of Cornelius:
“Jesus Christ is the Lord of all. You know what has taken place in all Judea, beginning from Galilee, after the baptism preached by John, that is, how God anointed Jesus of Nazareth with the Holy Spirit and power, and how he went around doing good and healing all those who were in the power of the devil – because God was with Him.
“We are witnesses of all the things that he accomplished in the region of the Jews and in Jerusalem. They killed him by hanging him on a tree, but God raised him up on the third day and willed that he should appear, not to the whole people but to witnesses whom God had already chosen – to us, who ate and drank with him after he rose from the dead. And he commanded us to preach to the people and to testify that he is the one whom God appointed as judge of the living and the dead.” (Acts 10:36-42)
The Rosary is a set form of prayers and meditations said with the help of a string of beads whereon to keep count of the prayers; the beads themselves are also called a Rosary. It consists of a string of beads divided into five sets (called decades), each of ten small beads and a larger one. A crucifix with two large and three small beads is always added but is not necessary.
Each decade is associated with one of twenty (originally fifteen) Mysteries of the Faith.
The method of saying the Rosary is to recite the Our Father on the large bead, the Hail Mary on each of the ten small beads, and the Glory be to the Father on the large bead – all the while meditating on the pertinent Mystery, which belongs to one of four groups called Joyful, Luminous, Sorrowful, and Glorious Mysteries.
These meditations on events in the Life of Jesus and his Mother are of the essence of this devotion. Hence, it is not a mechanical repetition of the vocal prayers, but a loving dwelling on God’s mercies, to which the prayers are a kind of accompaniment.
On the extra beads mentioned above, the Apostle’s Creed and Our Father are said, once each, and the Hail Mary is said three times in total. Then at the end of the Rosary, frequently the Marian Prayer “Hail, Holy Queen” is added and also the Litany of Loreto. (From The Greatest Marian Titles by Anthony Buono)