The Feast of Saint Mary the Virgin is celebrated on August 15 in the Episcopal Church. It is listed in the church calendar as one of several major Holy Days that "are regularly observed throughout the year" by Episcopalians. A feast day celebrating Mary has been observed on August 15 across the Eastern, Western, Coptic and Oriental churches dating back to at least the late 7th Century.
The 1979 Book of Common Prayer, in line with numerous other prayer book revisions across the Anglican Communion, restored the feast of Saint Mary the Virgin on August 15th to our calendar. It had been removed during the Reformation in part because there were already two “Marian” Holy Days in the calendar. In conjunction with restoring the Holy Day, the 1979 BCP modified these two other Holy Days by intentionally emphasizing Jesus, rather than Mary. The first of those modified days is the Presentation (February 2). Prior to the 1979 Prayer Book in the Episcopal Church this feast was officially referred to as “The Presentation of Christ in the Temple, commonly called, The Purification of Saint Mary the Virgin”. In 1979 the official title was changed to “The Presentation of Our Lord Jesus Christ in the Temple”. The second modified Holy Day was the Annunciation (March 25). Prior to the 1979 Prayer Book in the Episcopal Church this feast was officially referred to as “The Annunciation of the blessed Virgin Mary”. In 1979 the official title was changed to “The Annunciation of Our Lord Jesus Christ to the Blessed Virgin Mary”. In both cases (Presentation & Annunciation) the modified title and other minor liturgical changes to the day were intended to make it clear the celebration was a feast of our Lord Jesus Christ rather than a celebration of Mary. This allowed the Episcopal Church to restore to the calendar a feast celebrating Mary’s life and witness as a saint.
It is worth noting that the Feast of Saint Mary the Virgin is known under different titles in the Roman Catholic and Orthodox traditions, and those traditions celebrate an event. In the Roman Catholic Church, it is called “The Feast of the Assumption of the glorious and ever-blessed Virgin Mary”. In Orthodox churches it is known as “The Dormition of the most holy lady Theotokos and ever-virgin Mary”. In Catholic and Orthodox traditions, respectively, the Assumption and the Dormition are different names for the same event, Mary's departure from the earth, although the beliefs are not entirely the same. The Orthodox Church teaches that Mary died a natural death, like any human being; that her soul was received by Christ upon death; and that her body was resurrected on the third day after her repose, at which time she was taken up, bodily only, into heaven. Her tomb was found empty on the third day. Roman Catholic teaching holds that Mary was "assumed" into heaven in bodily form. Some Catholics agree with the Orthodox that this happened after Mary's death, while some hold that she did not experience death.
Elements of this tradition are found in the prayers and readings used on the feast of Saint Mary the Virgin as it is celebrated in the Episcopal Church, and certainly in the hymnody traditional for the day. For example, the opening Collect of the Day proclaims: “O God, you have taken to yourself the blessed Virgin Mary… [Grant that we] may share with her the glory of your eternal kingdom.” Also, in visual art and hymnody Mary is frequently depicted crowned as queen of heaven, in response to the psalmist who says, “On your right hand is the queen, adorned with the gold of Ophir.” That said, our tradition designates August 15th as a celebration of Mary’s entire life and Christian witness as recounted by the New Testament writers, rather than one event celebrated by later traditions but not found in the New Testament.