Dormition of the Mother of God different from Ascension of Jesus
Late 5th until 7th century
More Dormition traditions began surfacing in manuscripts during the late 5th century. Stephen Shoemaker characterised them as the "Palm of the Tree of Life" narratives, the "Bethlehem" narratives, and the "Coptic" narratives—aside from a handful of atypical narratives.The events of the Dormition of the Virgin and her burial are dealt with in several known apocrypha such as the "Liber de transitu Virginis Mariae" by Pseudo-Melito of Sardis (5th century), a passing reference in Pseudo-Dionysius the Areopagite, and narratives by Pseudo-Cyril of Jerusalem, and Pseudo-Evodius. Around this time, the first Dormition narratives among mainstream authors appear, namely Jacob of Serug and Theodosius of Alexandria. These late—5th and 6th century Dormition narratives come from differing communions, so not all of their content was accepted, but only the basic idea that the Virgin Mary blissfully rested and her soul was adopted by her Son Jesus Christ at Dormition.
According to Nikephoros Kallistos Xanthopoulos in his "History of the Church," Emperor Maurice (582–602) issued an edict which set the date for the celebration of the Dormition on August 15. After this time more "mainstream" Dormition narratives began appearing, their content still in part based upon the earlier, mostly anonymous, narratives. Modestus, Patriarch of Jerusalem (630–632) said at this celebration, while preaching, that he regrets the lack of specific information about the death of the Virgin Mary. According to Truglia, "John of Thessalonica," another 7th century author, "wrote a narrative admittedly based upon details found in earlier homilies." Theoteknos, bishop of Livias sometime between 550 and 650, also wrote a Dormition narrative similar in its content.
In Rome the feast called Dormitio Beatae Virginis was established by Pope Sergius I (687–701), borrowed from Constantinople.It is true that in Revelation death is presented as a punishment for sin. However, the fact that the Church proclaims Mary free from original sin by a unique divine privilege does not lead to the conclusion that she also received physical immortality. The Mother is not superior to the Son who underwent death, giving it a new meaning and changing it into a means of salvation. Involved in Christ's redemptive work and associated in his saving sacrifice, Mary was able to share in his suffering and death for the sake of humanity's Redemption. What Severus of Antioch says about Christ also applies to her: “Without a preliminary death, how could the Resurrection have taken place?” (Antijulianistica, Beirut 1931, 194f.). To share in Christ's Resurrection, Mary had first to share in his death. The New Testament provides no information on the circumstances of Mary's death. This silence leads one to suppose that it happened naturally, with no detail particularly worthy of mention. If this were not the case, how could the information about it have remained hidden from her contemporaries and not have been passed down to us in some way? As to the cause of Mary's death, the opinions that wish to exclude her from death by natural causes seem groundless. It is more important to look for the Blessed Virgin's spiritual attitude at the moment of her departure from this world. In this regard, St Francis de Sales maintains that Mary's death was due to a transport of love. He speaks of a dying “in love, from love and through love”, going so far as to say that the Mother of God died of love for her Son Jesus (Treatise on the Love of God, bk. 7, ch. XIII–XIV). Whatever from the physical point of view was the organic, biological cause of the end of her bodily life, it can be said that for Mary the passage from this life to the next was the full development of grace in glory, so that no death can ever be so fittingly described as a “dormition” as hers."Depiction in art
Byzantine art
In Byzantine art and that of later Orthodox schools the standard depiction shows the body of the Theotokos lying dead on a bed or bier.  Behind this stands, or floats, Christ holding a small body wrapped in a winding cloth, representing the soul of the Theotokos.  He often has a mandorla around him.  The apostles surround the bier, and the sky may have figures of angels, saints and prophets.  Christ is shown higher than the apostles, increasingly so in later centuries, so that he seems to be floating in the air above rather than standing on the ground like the apostles.  But his feet are always hidden behind the bier, leaving this ambiguous.
There are similarities between the traditional depictions of the Dormition of the Theotokos in Byzantine icons and the account of the death of the Egyptian Desert Father, Sisoes the Great. In both Christ is seen coming to receive the soul of the dying saint surrounded by an aureola or cloud of blinding light and accompanied by the angels and prophets. In Byzantine icons the other Christs shown surrounded by such a cloud of light are those also seen in icons of the Transfiguration, the Resurrection and the Last Judgment.  In some icons of the Dormition the Theotokos is depicted at the top of the icon in a similar aureola before the opening gates of heaven. This suggests that contemporary accounts of the deaths of the Desert Fathers accompanied by a sudden burst of light came to influence the development of the iconography of the Dormition.
not same as not identical to distinct from separate from unlike