This year, unusually, the Feast of the Annunciation of the All-Holy Lady Theotokos and Ever-Virgin Mary falls after Pascha. Indeed, Bright Wednesday is the very last day upon which the feast can fall (Thursday of the third week of Great Lent being the earliest).
Here is a brief explanation by S. V. Bulgakov of the origins of this festival:
The feast of Annunciation is dedicated to the commemoration and glorification of the event written about in the Gospel (Lk. 1:26-38). Ancient Christians had various names for this feast: "Conception of Christ", "Annunciation about Christ", "Beginning of Redemption", and “Annunciation of the Angel to Mary". And only in 7th century did it acquire the name for eternity the "Annunciation of the All-holy Theotokos". This feast was established by the ancient church. St. Athanasius (4th century) in his sermon on this feast names it first and specially honored in the order of feasts, as he recalls the beginning of the economy of the salvation of the people. In the 5th and 6th centuries because of heresies, which humiliate the person of the Mother of God and deform the teaching of the incarnation of Jesus Christ, presented separately, prompted the Church to magnify the celebration of the feast. For this time the divine services for the feast were enriched with many hymns in which the mystery of the incarnation of the Son of God and majesty of the Mother of God is opened. In the 8th century, St. John of Damascus and Theophanes, Metropolitan of Nicaea, composed a Canon for this feast, which is sung up to now. According to ancient Christian writers, in establishing the custom to celebrate the feast, the tradition of the Church places it on March 25, because the incarnation was accomplished on this day. Besides this day stands in natural agreement with December 25.
Bulgakov offers the following notes on how the service for Annunciation is celebrated during Bright Week:
Here, as usual, are some online resources to help you prepare for the Feast:On the second or third day of Pascha, on the eve Little Vespers is served and then the All-night Vigil, consisting of Great Vespers and Matins with features of the paschal divine service: the introductory psalm is replaced with the singing of "Christ is Risen!" with the verses "Let God arise", to the stichera for the Aposticha are added the stichera of Pascha with the refrain "Let God arise", after their ending the Troparion of Annunciation is sung three times, blessing of the loaves, then in Matins, instead of the Six Psalms, after the blessing of the priest, "Christ is Risen!" with the verses "Let God arise". After the Great Litany the Polyeleon of the feast, the antiphon of degrees in the 4th tone, the reading of the Gospel and the rest is festal Matins up to the canon; the canon of Pascha is added to the canon of the feast; instead of the Great Doxology after the stichera on the praises of the Resurrection and of the feast are the stichera of Pascha with the verses "Let God arise"; Matins with the two Litanies and the paschal dismissal. The Hours are paschal.
- Epistle reading: Hebrews 2: 11-18.
- Gospel reading: Luke 1: 24-38.
- St John Chrysostom, commentary (one, two) on the Epistle.
- Menaion service in Greek and Slavonic.
- St Ambrose of Milan, homily.
- St Jerome, homily.
- St Leo the Great, homily.
- St Gregory the Wonderworker, four homilies (one, two, three, four).
- St Proclus of Constantinople, homily.
- St John of Kronstadt, homily.
- Metropolitan Anthony of Sourozh, sermon.
- Metropolitan Hierotheos of Nefpaktos, essay.
- Fr Andrew Phillips, sermon.
- Fr Serpahim Holland, sermon.
- Fr Anthony Coniaris, sermon.
- Deacon Matthew Steenberg (now Hieromonk Irenaeos), relection.
- S. V. Bulgakov, explanation of the feast and liturgical notes.
- Greek Archdiocese, explanation.
- OCA, explanation.