Ascension Day commemorates Christ's bodily ascension into heaven forty days after the Resurrection (Acts 1:1-11, Luke 24:50-53). The feast always falls on a Thursday — forty days counted inclusively from Easter Sunday. The observance is ancient. Augustine of Hippo (Ep. 54 to Januarius, c. 400) already regarded the Ascension as a feast of apostolic origin, placing it alongside Easter and Pentecost as celebrations 'which the whole Church observes throughout the world.' Eusebius of Caesarea mentions it in the early fourth century. The Ascension stands as the christological complement to the Incarnation: at Christmas, God descends to take human nature; at the Ascension, human nature is taken up into the life of God. The theological implications are enormous — our flesh, our humanity, is now at the right hand of the Father. The BCP 2019 lists Ascension among the seven Principal Feasts, giving it the highest possible liturgical precedence. The ten days between Ascension and Pentecost have traditionally been kept as days of prayer and expectation, recalling the disciples' waiting in the upper room (Acts 1:12-14). Some Anglican and Roman churches transfer the observance to the following Sunday, though the BCP 2019 does not explicitly authorize this practice.

The Ascension has shaped both the liturgical calendar and Christian architecture. The tradition of extinguishing the Paschal Candle after the Gospel reading on Ascension Day — symbolizing Christ's departure from visible presence — was widespread in the medieval West, though modern practice varies. Egeria records a vigil service at the Imbomon (the traditional site of the Ascension on the Mount of Olives) in the 380s, and the feast was well established in both East and West by the fifth century. In the Byzantine tradition, the Ascension is one of the Twelve Great Feasts, and its icon — Christ ascending in a mandorla of glory while the apostles gaze upward and angels announce his return — is among the most theologically rich in the Eastern iconographic tradition. The two men in white (Acts 1:10-11) who promise Christ's return connect the Ascension forward to the Second Coming, making it both a feast of accomplished salvation and eschatological hope. The collect in the BCP 2019 focuses on the ascent of hearts and minds: 'May our hearts and minds also there ascend, and with him continually dwell.' The season between Ascension and Pentecost — sometimes called the 'Great Novena' — is a period of prayer for the coming of the Spirit.

Dunstan was born in 909 near Glastonbury into a family connected to the West Saxon royal house. He was educated at Glastonbury Abbey and showed early talent for music, metalwork, and illumination — arts he practiced throughout his life. It is from this work at the forge that the later medieval tradition draws his most famous image: that while making liturgical vessels he was tempted by the devil and seized him by the nose with red-hot tongs. The episode is unknown to his earliest biographer ('B.,' writing in the 990s) and first appears in Osbern of Canterbury more than a century later; it nevertheless became the iconographic signature by which Dunstan was known throughout the English Middle Ages.

His early career was politically turbulent. He was a courtier under King Æthelstan but was expelled from court on accusations of practicing black magic (likely the suspicion of a jealous rival). After a period of uncertainty, King Edmund appointed him Abbot of Glastonbury around 940. Under Dunstan's leadership, Glastonbury became the model for the English Benedictine revival: he enforced strict observance of the Rule, built up the library, promoted the arts, and trained a generation of monks who would become bishops and reformers.

Dunstan served as chief adviser to successive kings — Edmund, Eadred, and Edgar. Under Edgar (959–975), the monastic reform reached its peak. Dunstan, together with his fellow reformers Æthelwold (Bishop of Winchester) and Oswald (Bishop of Worcester, later Archbishop of York), reorganized English monasticism along Continental Benedictine lines. The Regularis Concordia, a unified monastic customary drawn up at the Council of Winchester (c. 970), codified their reforms.

As Archbishop of Canterbury (959–988), Dunstan wielded enormous ecclesiastical and political power. He crowned Edgar in an elaborate ceremony at Bath in 973 — a liturgical event that established the pattern for English coronations thereafter. After Edgar's death, Dunstan navigated the difficult succession between Edward the Martyr and Æthelred the Unready.

Dunstan died on May 19, 988, in his eightieth year. His last recorded public act was preaching three sermons on Ascension Day, during which he is said to have announced his imminent death.

The most famous legend about Dunstan tells that one night, while he was at work in his forge, the devil appeared at the window in human disguise — in some tellings as a beautiful woman — and sought to draw him into temptation. Dunstan, recognizing his adversary, snatched up the red-hot tongs from the fire and seized the devil by the nose, holding him fast as he howled and writhed; the cries (a later English rhyme adds) were heard three miles off before he was at last released. The story connects to Dunstan's known skill as a metalworker and became his defining iconographic attribute. It first appears, however, in Osbern of Canterbury's Vita (c. 1090), over a century after Dunstan's death; it has no early attestation and belongs to the classic devil-encounter hagiography of the post-Conquest period.

The earliest vita ('B.') records that Dunstan experienced visions and that his appointment to Glastonbury was divinely confirmed, but these are relatively restrained compared to the later tradition. 'B.' also records miracles at Dunstan's tomb, following standard convention.

Dunstan's prediction of his own death on Ascension Day is reported by the earliest sources and has the character of a deathbed prophecy topos, though the specific liturgical context (three sermons on the feast) gives it circumstantial weight.