The Feast of the Assumption of the Blessed Virgin Mary is celebrated each year on August 15th. The feast commemorates Mary’s death and the assumption of her body into Heaven. It is the most important feast that honors the Blessed Virgin, because it signifies Mary’s passing into eternal life. Therefore, it is a Holy Day of Obligation unless otherwise noted.
The earliest reference in print that Mary’s body was assumed into Heaven is in a document written in the 4th century and was called “The Falling Asleep of the Holy Mother of God.” It is written in Apostle John’s voice. Jesus had entrusted the Apostle John with caring for His mother. In the document there is a recounting of Mary’s death in Jerusalem or Ephesus, where John lived.
The Feast of the Assumption was first celebrated in the East during the sixth century and was known as the Dormition, which means “the falling asleep.” By the thirteenth century the feast was celebrated universally. Pope Pius XII declared that as a dogma of the Catholic Church, “that the Immaculate Mother of God, the ever Virgin Mary, having completed the course of her earthly life, was assumed body and soul in heavenly glory.”
“In the bodily and spiritual glory which she possesses in heaven, the Mother of Jesus continues in this present world as the image and first flowering of the Church as she is to be perfected in the world to come (cf. 2 Peter 3:10), as a sign of certain hope and comfort for the pilgrim People of God” (Vatican II, Dogmatic Constitution on the Church, 68).