The rosary of the Blessed Virgin Mary is a form of prayer (vocal or mental), consisting of 15 decades of Hail Marys, said on beads, each decade preceded by an Our Father and followed by a Gloria, during the recitation of which the mind meditates or dwells on the principal mysteries of the life, death, and resurrection of Our Lord. This is the true Rosary, sometimes called the Dominican, or Rosary of Saint Dominic, because its origin has been traditionally attributed to that saint. As a rule, five decades are recited at a time. Other rosaries are more properly called beads, as the beads of the Immaculate Conception, the beads of the Seven Dolors, the Blessed Sacrament beads. The Rosary is the most popular of the non-liturgical prayers. It has been richly indulgenced by many popes. The beads should be blessed by a Dominican or any other duly authorized priest. Pope Leo XIII instituted the Month of the Holy Rosary (October) and added the invocation “Queen of the Most Holy Rosary” to the Litany of Loreto in 1833.