There have been various rosary like prayers, both Pagan, Jewish and Christian. The most common of the Catholic forms of the Rosary, (Dominican Rosary) was composed around 1100, the modern form in Lay people who didn’t have copies of Scripture or the Breviary and lay people and religious who were illiterate would substitute 150 Pater Nosters (Our Fathers) or Aves (Hail Marys) in place of the 150 Psalms they could not read.
The prayers were originally counted by transferring pebbles from one bag to another, but soon enough Christians began to tie a rope with knots on which to count. Desert monastics were in the habit of reciting a specified number of prayers daily and such a method of keeping track of them is natural. In the life of the Egyptian Abbot Paul (d. A. D. 341), we read that he used to collect three hundred pebbles every day and throw away each one as he finished the corresponding prayer he was accustomed to recite. This evolved further into using beads or pieces of wood in place of the knots, and this soon came to be called the “Psalter of the Laity.” Around the end of the first millennium, Rosaries contained the present five decades (sets of ten beads), with the Ave beads shaped like white lilies for the purity of the Virgin, and the Pater beads shaped like red roses for the wounds and Passion of Christ.