Standing before a joyful crowd packing St. Peter's square in November 1950, Pope Pius XII declared "that the Immaculate Mother of God, the ever Virgin Mary, having completed the course of her earthly life, was assumed body and soul to heavenly glory." By this proclamation the pope defined belief in Mary's assumption into heaven as a dogma, or divinely revealed teaching, of the Catholic Church. However, belief that Mary "fell asleep" at the end of her life and was miraculously transported to heaven dates back to the early medieval church and has been a source of devotion for centuries in the Catholic and Orthodox traditions.

Although Scripture reveals nothing about the manner of Mary's death, traditions surrounding her life after Christ's resurrection soon arose in the church. References to her dormition (literally "falling asleep") and assumption appear as early as the seventh century. In the most famous account, St. John Damascene (d. 749) passed on a story reportedly told at the Council of Chalcedon (451) that Mary had died in the presence of the Apostles, but when they opened her tomb they found it empty, "wherefrom the Apostles concluded that the body was taken up to heaven." By the end of the eighth century, feasts celebrating Mary's dormition included prayers referring to her assumption as well.

Mary's bodily assumption into heaven has traditionally been celebrated as the firstfruits of Christ's resurrection. Catholic and Orthodox believers affirm that because Mary was assumed body and soul into heaven, she experiences the resurrected glory for which all Christians hope. Vatican II teaches that "she shines forth on earth … a sign of certain hope and comfort to the pilgrim people of God." Her assumption serves as ...