Maundy Thursday commemorates the events of the night before Christ's crucifixion: the Last Supper, the institution of the Eucharist, the washing of the disciples' feet, and the agony in Gethsemane. The name 'Maundy' derives from the Latin mandatum novum — 'a new commandment' — from John 13:34, spoken after Jesus washed his disciples' feet. The earliest evidence of a distinct liturgical observance on this day comes from the late fourth century. The pilgrim Egeria, writing around 384, describes elaborate Jerusalem services including an afternoon Eucharist at the Martyrium basilica and an evening station at the Imbomon (the traditional site of Jesus's teaching on the Mount of Olives), concluding with a nighttime procession to Gethsemane. By the time of the Apostolic Constitutions (c. 380), the day was established as a fast day. Augustine of Hippo (Ep. 54, to Januarius) attests that by around 400 the day was celebrated with both a morning and evening Eucharist — the evening celebration deliberately recalling the hour of the Last Supper. The foot-washing ceremony (mandatum or pedilavium) became a standard Western liturgical practice by the early medieval period. The seventh-century Ordo Romanus documents the stripping of altars, and the Gelasian Sacramentary provides proper prayers for the day. The Eastern churches developed the day under the name 'Holy and Great Thursday,' with emphasis on both the Last Supper and the Passion beginning at Gethsemane.

The liturgical customs of Maundy Thursday are among the richest in the Christian year. The stripping of the altar after the evening Eucharist — removing cloths, candles, and ornaments to leave the sanctuary bare — dramatically enacts the desolation of Gethsemane and the abandonment of Christ by his disciples. This practice is attested from at least the seventh century (Ordo Romanus) and may be older. The washing of feet, whether performed by the presider on members of the congregation or as a mutual act, recovers the dominical command of John 13 and has been practiced in both East and West, though with varying emphasis — in England, the monarch's participation in the Royal Maundy is documented from the thirteenth century. The reservation of the Blessed Sacrament and the watch before the altar of repose recall Christ's words in Gethsemane: 'Could you not watch with me one hour?' (Matthew 26:40). The Tenebrae office — a service of progressive darkness in which candles are extinguished one by one — is historically associated with the Triduum evenings, and the BCP 2019 provides for it on this night. The evening marks the beginning of the Paschal Triduum — the three-day liturgy spanning Thursday evening through Easter Day that forms the single most important liturgical event of the Christian year. The collect focuses on the institution of the Eucharist specifically, grounding the day's devotion in sacramental theology: what was given on this night continues to be received at every celebration of the Lord's Supper.

Anselm was born in Aosta in the foothills of the Alpine region and trained at the monastery of Bec in Normandy under the celebrated Lanfranc. He became prior (1063) and then abbot (1078) of Bec, earning a reputation across Europe for his theological acumen and monastic reformism. In 1093, King William II appointed him Archbishop of Canterbury, though he accepted with reluctance. His tenure was marked by fierce disputes over the investiture controversy and Church-State authority. Anselm insisted that the Church's independence from secular rulers was non-negotiable; he resisted both William Rufus and his successor Henry I, going into voluntary exile (1097–1100 and 1103–1106) rather than compromise ecclesiastical liberty. During his final years at Canterbury, he maintained extraordinary intellectual vigor, debating theology and revising his works until his death. Eadmer, his companion and secretary, records that Anselm continued deep theological discussion on his deathbed. His life embodied the conviction that reason and faith must work together in seeking God's truth.

Anselm's theological legacy rests on two pillars: the ontological argument for God's existence (Proslogion, 1077–78) and the satisfaction theory of the atonement (Cur Deus Homo, 1098). The ontological argument — that God is 'that than which nothing greater can be thought,' and that such a being must exist in reality as well as in the mind — has generated continuous philosophical debate from Gaunilo's contemporary rebuttal through Kant's critique to Plantinga's modal reformulation. Cur Deus Homo reframed atonement theology by arguing that only a God-man could offer the satisfaction owed to divine honor by human sin, displacing the earlier ransom theory that had dominated patristic thought. Both works exemplify Anselm's method of 'faith seeking understanding' (fides quaerens intellectum) — not proving faith by reason alone, but pressing reason into service within the life of faith. His monastic writings, especially the Prayers and Meditations, reveal a devotional warmth that balances his intellectual rigor. The prayers to the Virgin Mary and to St. Paul anticipate later medieval affective piety while remaining grounded in scriptural imagery. Anselm was canonized in 1494 and declared a Doctor of the Church in 1720. His influence runs through Aquinas (who adopted and modified the satisfaction theory), Descartes (who revived the ontological argument), Barth (who devoted his first major work to Anselm's theological method), and contemporary analytic philosophy of religion.