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.

The earliest evidence for a March 25 Annunciation feast comes from sixth-century Constantinople (c. 555, under Justinian I). In the Latin West, the Sacramentary of Pope Gelasius (d. 496) and the Sacramentary of Pope Gregory (d. 604) mention it, though scholars debate whether the feast originated in their time or later. The first certain reference is the 656 Council of Toledo, which describes the feast as 'celebrated throughout the church.' The Spanish Church initially observed the Annunciation on December 18 rather than March 25, and the tenth Synod of Toledo (656) confirmed this local usage.

The Quinisext Council (Constantinople, 692) allowed the Annunciation as an exception to the rule against feast days during Lent — a concession reflecting the feast's importance and the practical tension between its fixed March 25 date and the moveable Lenten calendar. Modern Western practice transfers the feast when it falls in Holy Week or Easter Week.

The relationship between March 25 and December 25 is fundamental. The Calculation Hypothesis holds that early Christians identified March 25 as both the date of Christ's death and his conception (following a Jewish tradition that great persons die on the date of their conception or birth). Nine months from March 25 yields December 25. Whether the Annunciation date generated the Christmas date or vice versa remains debated, but the theological logic is clear: the Incarnation is a single mystery whose beginning (conception) and manifestation (birth) are intimately linked.

In England, March 25 was known as Lady Day and served as the legal New Year from 1155 to 1752, when the Gregorian calendar moved the new year to January 1. Lady Day was the first of four English Quarter Days (with Midsummer, Michaelmas, and Christmas), marking when agricultural contracts began and rents were due. The theological symbolism was intentional: the year began where the story of salvation began, with the Word becoming flesh.

Irenaeus of Lyons (c. 180) developed the foundational New Eve theology: 'The knot of Eve's disobedience was untied by Mary's obedience.' Just as death entered through a woman's 'no' to God's design, salvation entered through a woman's 'yes.' This patristic theme — Mary as the faithful counterpart to faithless Eve — became central to Christian reflection on the Annunciation across all traditions.