Easter is the feast of the Resurrection of Jesus Christ from the dead — the oldest, highest, and most central celebration of the Christian year. Every other movable feast and fast is calculated from it; every Sunday is a weekly Easter. The date is determined by the Paschal computation established at the Council of Nicaea (325): Easter falls on the first Sunday after the first full moon on or after the vernal equinox (March 21), placing it between March 22 and April 25. The earliest Christians appear to have observed an annual Pascha from a very early period, though the precise origins are debated. The Quartodeciman controversy of the second century — whether to celebrate the Pascha on Nisan 14 (regardless of the day of the week) or always on a Sunday — attests that the observance was already widespread and deeply important by the mid-100s. Polycarp of Smyrna reportedly discussed the matter with Anicetus of Rome around 155 (Eusebius, HE 5.24), and the issue was sharp enough to prompt Victor of Rome to threaten excommunication of the Asian churches, a threat moderated by Irenaeus's famous appeal for peace. The Nicene resolution in favor of the Sunday observance became universal in the mainstream Church, though some groups maintained the Quartodeciman practice for centuries. The Great Vigil of Easter is among the most ancient liturgies in Christianity, with roots traceable to at least the third century (Apostolic Tradition). By the fourth century, Egeria describes an elaborate Jerusalem vigil with baptisms, and Augustine attests a similar pattern in North Africa.

The Great Vigil, which the BCP 2019 describes as 'the first liturgy of Easter Day,' begins in darkness. The Paschal Candle is lit from new fire — a symbol of Christ as the light of the world entering the darkness of the tomb. The Exsultet, the great hymn of praise to the Paschal Candle, is among the most magnificent pieces of Christian hymnody, attested from at least the fourth century (Ambrose may have composed an early version). The vigil readings trace salvation history from creation through the Exodus to the prophets, building to the proclamation of the Resurrection Gospel. Historically, the Vigil was the primary occasion for baptism — new Christians dying and rising with Christ through the waters, emerging to receive their first Eucharist on the night of the Resurrection. The BCP 2019 provides for baptism or renewal of baptismal vows at the Vigil. The Easter morning liturgy opens with the Paschal greeting: 'Alleluia! Christ is risen! / The Lord is risen indeed! Alleluia!' — a form attested across virtually every Christian tradition. The fifty days of Eastertide that follow (through Pentecost) are treated as a single unbroken feast — no fasting, no kneeling for prayer, Alleluias throughout. Easter eggs, the custom of which is documented from at least the thirteenth century, symbolize the sealed tomb and new life breaking forth. Easter is not a day but a season.

Alphege (Ælfheah) was born around 954 and entered monastic life as a young man, eventually becoming an anchorite at Bath known for his extreme asceticism and spiritual discipline. He was appointed Bishop of Winchester in 984 and served with distinction, building a reputation as a disciplinarian and reformer of monastic practice before being elevated to Archbishop of Canterbury in 1006, succeeding Ælfric.

His tenure as archbishop coincided with the most devastating phase of the Viking raids on England. In September 1011, a Danish army commanded by Sweyn Forkbeard besieged and captured Canterbury, taking Alphege prisoner along with many of his clergy and citizens. The Danes demanded a ransom of three thousand pounds of silver—an enormous sum that Alphege refused to pay, insisting that the wealth of the Church belonged to the poor and could not be used to purchase one man's freedom, even his own. This decision reflected a theological conviction that the Church's resources were sacred and inviolable.

For seven months Alphege remained in captivity, reportedly maintaining his episcopal ministry and celebrating Mass in captivity. On April 19, 1012, at a feast in Greenwich, his captors—reportedly drunk on wine—grew impatient with his refusal to authorize ransom and attacked him. According to the Anglo-Saxon Chronicle (D manuscript), they pelted him with ox bones and remnants of their meal. A Danish Christian named Thrum, moved by compassion at the violence, struck Alphege with the back of an axe, presumably to end his suffering. He died of his wounds shortly after.

Alphege's body was initially left with the Danes but was soon recovered and taken to London, where it was given honorable burial. His cult grew rapidly, and by the early 12th century he was widely venerated as a martyr-bishop whose death exemplified pastoral sacrifice. He remained the most widely commemorated archbishop of Canterbury until Thomas Becket's canonization in 1173.

Traditionally, Alphege was venerated as a martyr-confessor whose steadfastness under captivity exemplified apostolic courage. According to Osbern of Canterbury, miracles of healing occurred at his tomb almost immediately after his martyrdom. When his body was translated from London to Canterbury in 1023 by Archbishop Æthelnoth, it was reportedly found to be incorrupt—a sign interpreted as confirmation of his sanctity, though the details of the translation account may be hagiographic embellishment.

A later tradition held that Alphege appeared in vision to Lanfranc, the post-Conquest Archbishop of Canterbury, urging the restoration of his shrine. The cult of Alphege was especially strong in Canterbury and Winchester, the two sees he had served. Uniquely among archbishops of Canterbury, Alphege was invoked as an intercessor by later martyred bishops, most notably by Thomas Becket, who reportedly prayed at Alphege's tomb before his own martyrdom in 1170 and saw his predecessor as a model of episcopal courage.