It’s the season of Advent and at St Luke’s we are singing “O come, O come, Emmanuel” through the whole season, adding a verse each week, which is not necessarily a usual way to sing a hymn, but is not too distant from the spirit of this hymn’s ancestors, the so-called Great “O” Antiphons. Let’s look at the history of these treasures of Advent liturgy, starting with the origin of antiphons themselves!
An antiphon is a liturgical chant sung in association with a psalm or canticle, sung either throughout, between verses of the psalm, or just at the beginning and end, framing the psalm. The antiphon has its own tune (it might be related to the psalm tune), and its text might be either a verse from that psalm, an Alleluia, or a text composed to comment upon the psalm in the context of the day, hour, season or occasion on which it is sung. As Margot Fassler notes, “the composer of antiphon texts and music was a creator of commentary as well, in this case, of exegesis of the texts of the Psalter.”
Antiphons are significant because psalm-singing has been a large and central part of worship since the early days in which Christians were first allowed to build churches. The people would gather at those buildings in the mornings and evenings to sing psalms. For church-goers, this custom persisted mainly in the form of Vespers (evening hymns). In the monasteries, more times in which to sing psalms were added – eventually, up to eight times a day, every day! So antiphons are particularly prominent in the monastic tradition. Many are recorded in large music books (called antiphoners or antiphonals) that several people can sing from at the same time.
The Great “O” Antiphons frame the singing of the Magnificat in Vespers for several days at the end of Advent, a different antiphon every day for each of the days leading up to Christmas. By the late middle ages, the church might enjoy anything from seven to twelve different antiphons for these days, depending on local tradition; but at least seven of them can be traced back to as early as the 8th century. Each one gives a different name for Jesus and refers to a prophecy about the coming Messiah:
O Sapientia (Wisdom)
O Adonai (Lord of Israel)
O Radix Jesse (Root of Jesse)
O Clavis David (Key of David)
O Oriens (Dayspring)
O Rex Gentium (King of the nations)
O Emmanuel (God with us)
Catholic Newman Center at University of Washington has some general background on the O Antiphons and one of the best renditions of “O Sapientia” that I’ve heard:
If you know the song “O come, O come, Emmanuel,” then you can probably see its connection to the O Antiphons already. By the 18th century (the earliest surviving written copy comes from this period), songwriters had composed a Latin hymn (“Veni, veni Emmanuel”) that synthesised the antiphons of all seven days into one song; each verse is a metrical paraphrase of one antiphon. The order of the verses is different to the order in which the antiphons are sung, so that Emmanuel is named in the first verse (cf the final antiphon). In 1851, the gifted translator John Mason Neale made the English translation that we now know as “O come, O come, Emmanuel” and in 1854, his colleague Thomas Helmore paired it with the 15th-century tune that is now so familiar.
The common thread here is that singing so many names of Jesus and prophecies regarding him is a way of welcoming and honouring him as the anticipation builds for the celebration of his nativity. But look what a journey this text has come, from antiphon to hymn: from a set of framing texts sung with the Magnificat over several days, to a sequence of verses in a single song, and now, in turn, these antiphon texts are framed by the refrain of the hymn: “Rejoice! Rejoice! Emmanuel shall come to thee, O Israel.” The texts that originally commented upon and contextualised the canticle are now commented upon and contextualised by this bidding to rejoice in hope.
 Margot Fassler, “Hildegard and the Dawn Song of Lauds: An Introduction to Benedictine Psalmody,” in Psalms in Community: Jewish and Christian Textual, Liturgical and Artistic Traditions, eds. Harold Attridge and Margot Fassler (Leiden: Brill, 2004), 222.
 Craig Wright, Music and Ceremony at Notre Dame of Paris, 500-1550 (Cambridge: Cambridge University Press, 1989), 106-7.