Wednesday of Holy Week carries the informal name 'Spy Wednesday' — a medieval English designation recalling Judas Iscariot's agreement to betray Jesus to the chief priests (Matthew 26:14–16, Mark 14:10–11, Luke 22:3–6). The Synoptic Gospels place this arrangement two days before Passover, and the tradition of associating Wednesday with Judas's treachery is attested from at least the early medieval period. In the Byzantine tradition, this day is called 'Holy and Great Wednesday' and is associated with the anointing at Bethany (Matthew 26:6–13), where the woman's lavish devotion stands in deliberate contrast to Judas's calculating betrayal — the one pouring out costly nard, the other selling his Master for thirty pieces of silver. The Western lectionary tradition has varied over the centuries in which Gospel passage it assigns: some years emphasizing the anointing, others the conspiracy. The day also holds typological significance as the last 'ordinary' day before the Triduum begins at sundown on Thursday. In the early Church, Wednesday and Friday were already established as station days — days of fasting and prayer — which gave Wednesday of Holy Week a natural intensification of the regular Wednesday fast. The overlap with Passover preparation in Jesus's own time adds a further layer: as the Jewish community prepared lambs for slaughter, the Lamb of God was being handed over by one of his own.

The liturgical observance of Wednesday in Holy Week has been shaped by two parallel streams. In the East, the emphasis falls heavily on the anointing at Bethany and the contrast between devotion and betrayal; Byzantine hymnography for this day is rich with references to 'the sinful woman' who recognized Christ while Judas did not. In the West, the medieval tradition gave the day its popular name 'Spy Wednesday,' and the focus shifted more toward the conspiracy narrative. The BCP 2019 places this day within the protected days of Holy Week — no other observance can displace its propers. When the Annunciation (March 25) falls during Holy Week, it is transferred, illustrating the absolute liturgical precedence of these days. Some parishes observe Tenebrae services on Wednesday evening as anticipatory preparation for the Triduum, though the BCP itself assigns the principal Tenebrae elements to Maundy Thursday. The day serves as a hinge between the teaching ministry of Holy Week's earlier days (when Jesus taught in the Temple) and the Passion narrative that begins in earnest at the Last Supper.

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.