Among his numerous contributions to the Christian church, the hymns of St. Ambrose, bishop of Milan (340-397) have pride of place.  Veni redemptor gentium (Come, Redeemer of the Gentiles), indirectly attributed to Ambrose by St. Augustine, remains in the Roman Liturgy of the Hours to this day, as the hymn for the Octave before Christmas.

Veni, redemptor gentium,
ostende partum Virginis;
miretur omne saeculum:
talis decet partus Deum.

O come, Redeemer of the earth,
and manifest thy virgin-birth.
Let every age in wonder fall:
such birth befits the God of all.

Particularly popular in medieval Germany, Veni redemptor gentium was one of the initial hymns Martin Luther (1483-1546) adapted for congregational use in the wake of the Reformation.  Translated into German as Nun komm, der Heiden Heiland with a metricized melody, it first appeared in the Erfurt Enchiridion of 1524.   Swiftly, it became the Hymn of the Day for the First Sunday in Advent in Lutheran churches; over the centuries, it’s been set for organ and/or choir by numerous composers.  Of course, the cantata and chorale prelude settings by Johann Sebastian Bach (1685-1750) stand out:

But the legacy of this ancient hymn continues into the modern day, with organ settings by modern composers such as Paul Manz (1919-2009) …

… and its numerous English translations, including the composite version found in 2006’s Lutheran Service Book.  In the video below, the hymn begins at 1:57, following a Luther quote spoken over a chorale prelude by Dietrich Buxtehude (1637-1707).

Savior of the nations, come, Virgin’s Son, make here Your home!
Marvel now, O heav’n and earth, That the Lord chose such a birth.

Not by human flesh and blood, By the Spirit of our God,
Was the Word of God made flesh—Woman’s offspring, pure and fresh.

Here a maid was found with child, Yet remained a virgin mild.
In her womb this truth was shown: God was there upon His throne.

Then stepped forth the Lord of all / From His pure and kingly hall;
God of God, yet fully man, His heroic course began.

God the Father was His source, Back to God He ran His course.
Into hell His road went down, Back then to His throne and crown.

For You are the Father’s Son / Who in flesh the vict’ry won.
By Your mighty pow’r make whole / All our ills of flesh and soul.

From the manger newborn light / Shines in glory through the night.
Darkness there no more resides; In this light faith now abides.

Glory to the Father sing, Glory to the Son, our king,
Glory to the Spirit be / Now and through eternity.

— Rick Krueger