Complete step-by-step guide to the Catholic Rosary — all four Mysteries, every prayer, and the order.
The Rosary in its current form developed gradually between the 12th and 16th centuries. Tradition attributes its institution to medieval saints — particularly Saint Dominic (1170-1221), who reportedly received it from the Virgin Mary in a vision. The structure of three sets of Mysteries (Joyful, Sorrowful, Glorious) was formalized in the 16th century.
For 400 years, those three sets totaled 15 decades. In 2002, Pope John Paul II added the Luminous Mysteries (the "Mysteries of Light") in his apostolic letter Rosarium Virginis Mariae, bringing the total to 20 decades and covering the public ministry of Christ — which the original 15 Mysteries had jumped over (from his finding in the Temple at age 12 directly to his Agony in the Garden).
The Rosary remains the most widely-prayed Catholic devotion after the Mass itself. October is traditionally the "Month of the Rosary" in Catholic devotion, with October 7 the Feast of Our Lady of the Rosary.