History of the Rosary
Tradition has it that the Rosary was taught to St. Dominic, at Toulouse (France), about the year 1206. It was supposedly given to him by Our Lady, as a help against the great heresy of the day - the Albigensian heresy. This heresy was named after the town of Albi, (France) from which it originated.
The Albigensians taught that all matter, including flesh, was evil, that mankind was basically attracted to evil, and that suicide to prevent further sins was a good and noble thing to do.
But Rosarys of different kinds had been around for many centuries prior to then - even back as far as the early days of the hermits in the deserts, who used either pebbles to count their prayers, or knots tied in a piece of cord, in the same way as we today count our prayers on Rosary Beads.
St. Dominic taught the Rosary, and it became the weapon which defeated that heresy. Thereafter the Dominican Order was responsible for the spread of the Rosary, and in fact what we have been praying for several hundred years is known as the "Dominican Rosary" - certain other Orders having their own "Rosary" with differing meditations and even differing numbers of beads.
It is thought in some circles that the Rosary originally developed from the custom of the clergy praying the 150 Psalms of David. Since most people apart from clergy were illiterate, and could not remember all 150 Psalms, they developed the practice of praying 150 Our Fathers or Pater Nosters. Rosary Beads which came into use to help count the 150 prayers were for a long time called "Pater Nosters". In London there is still (or was until very recently) a street which used to contain all the shops that manufactured Rosary Beads, and it is called Pater Noster Row.
The number 150 is the number of "Hail Marys" that are prayed in the traditional 15 decade Rosary - the three sets of Mysteries - the Joyful, Sorrowful and Glorious. Now (as from 16th. October 2002) we have four sets of Mysteries, Pope John Paul II having added the Luminous Mysteries.
The five decades of the Luminous Mysteries cover some major events in the life of Jesus, or basically in the last three years of His life, when He "went public".
These are His Baptism in the Jordan River; His first public miracle at the Wedding Feast at Cana; His proclamation that "the kingdom of God is at hand";
His Transfiguration on Mount Tabor; and His Institution of the Eucharist at the Last Supper.