August 15 marks one of the most important Marian Feasts on the Roman Catholic calendar -- The Feast of the Assumption of the Blessed Virgin Mary. In fact, feast day is described by some as the most important Marian Feast. On this date, we Roman Catholics celebrate the Assumption of the Body of Our Lady in Heaven. We believe that the body and soul of Our Lady was taken up into Heaven after Her death.
The Feast of the Assumption of the Blessed Virgin Mary was celebrated informally for centuries. On November 1, 1950, Pope Pius XII declared this Dogma in his Apostolic Constitution Munificentissimus Deus. Since the 1950's, Catholics have celebrated the Feast of the Assumption as a Holy Day of obligation.