The words of this motet come from the antiphon for the service of vespers for Christmas Day.

Jan Pieterszoon Sweelinck (1562 – 1621) was a Dutch harpsichordist, organist, composer and teacher. He was organist and carillonneur of the Oude Kerk (Old Church) in Amsterdam from 1580 until his death, and is buried in the church. Since the Calvinists saw the organ as an intrusive and unwelcome instrument, and forbade its use during services, Sweelinck was employed in a civic capacity by the municipal authorities in Amsterdam to provide one hour of organ music before each service and to write a cappella (unaccompanied) choral music for civic and ceremonial occasions as required. He was the first composer to write separate and independent parts for the pedals in organ music, and was a great early exponent of the fugal style, pioneering and establishing the form which was later to be mastered by Bach. Sweelinck was the last, and possibly most gifted, of a great tradition of Dutch and north European composers, and his death concluded a rich and golden period in the Netherlands’ musical history. His polyphonic setting of the entire psalter has been justifiably called a unique monument to this history, and one unequalled anywhere else in the sphere of sacred music. His surviving output numbers 254 vocal works (including 153 psalm settings, 33 secular chansons and 39 madrigals), over 70 keyboard works, and numerous other works for consorts of viols, recorders and lutes. None of his vocal works is in his native language, they being in either Latin or French, and 14 of his sacred motets, including this one, conclude with extended codas on the word Alleluia. This motet, written in 1619, is divided into clearly delineated sections, each one opened by an exclamation in the tenor part. The rhythmic pulse constantly shifts between triple and duple time.

For many people worldwide the start of Christmas is marked by listening to the Festival of Nine Lessons and Carols on Christmas Eve. This wonderful service, devised by Bishop Benson (the first ever Bishop of Truro in 1877 and later Archbishop of Canterbury) and modified by Eric Milner-White in 1918, has been broadcast live at 3 pm from the Chapel of King’s College Cambridge by the BBC every year except one since 1928.  The service always ends with the organ voluntary In Dulci Jubilo by J. S. Bach.

This piece is one of Bach’s many Chorale Preludes. These are organ pieces which use a hymn melody, altered and extended in some way, but still perfectly recognisable to the Lutheran congregations who were the first to hear them, as the basis for composition. Bach treats the hymn melodies in a variety of different styles: sometimes they are presented in augmented note values with an elaborate accompaniment; sometimes they are heavily ornamented; sometimes the melody is hidden in the middle of the texture or in the bass line. This setting of In Dulci Jubilo (Bach made at least two separate preludes out of this melody at various times), written between 1708 and 1718, when Bach was in Weimar, is in fantasia style. The piece is almost a toccata (from the Italian toccare – to touch), and the well-known melody is presented in short, single line, dramatic, harmonised statements, in between which there are flamboyant, fantasia-style passages of a celebratory and almost improvisatory nature which later subsume the melody.