Bach's Christmas Oratorio dates from the winter of 1734/5. To quote from the title-page of the original libretto, it was "performed at Christmas in the two main churches in Leizpig", its six parts being presented on six separate days, namely, the first, second and third days of Christmas, the feast of the Circumcision (New Year's Day), the first Sunday in the New Year and the feast of the Epiphany. Part I was first heard at St Nicholas's on Christmas morning and at St Thomas's in the afternoon. Parts II, IV and VI were also performed twice, but at St Thomas's in the morning and St Nicholas's in the afternoon. Parts III and V could be heard only during the morning service at St Nicholas's, its feast days being less important within the church calendar. St Nicholas's was Leipzig's principal church, making it all the more surprising that it had no Kantor of its own. Instead, the Kantor of St Thomas's, who was also the town's director of music, had to provide music for St Nicholas's. In the course of his twenty-seven-year tenure as Thomaskantor, Bach conducted considerably more performances at St Nicholas's than at St Thomas's.
It has become customary to describe the six parts of the Christmas Oratorio as cantatas, but this term is inaccurate in two respects. First, the word "cantata" at this period generally meant a secular work for solo voice and instruments, whereas Bach always used the terms "church piece" or "concerto", never "cantata", to describe the figural works that he wrote for Sunday worship. And, secondly, a closer look at the individual parts of the Christmas Oratorio reveals that they are not independent compositions: not only are they related to the day's lesson but they form a continuous narrative compiled from the different Gospel accounts. In other words, the oratorio's cyclical design affects the selection and positioning of its individual parts, with the result that the distribution of the lessons between the six parts occasionally departs from the division observed in church. The prologue from St John's Gospel prescribed for the third day of Christmas has nothing to do with the Christmas story in its narrower sense and has therefore been omitted. Instead, the lesson for the second day of Christmas has been transferred to the third day, and the lesson for the first day has been divided between the first and second days, a change that has the dramaturgical advantage of ensuring that the scene with the shepherds in Part II is invested with extra weight. In much the same way, the flight into Egypt that forms part of the lesson for the first Sunday in the New Year has been cut as it cannot take place before the visit of the Three Wise Men, which is linked in turn to the feast of the Epiphany. The liturgical lacuna has been filled by stretching out this visit over Parts V and VI.
We do not know who wrote the free texts that form the third layer of the work alongside the Gospel narrative and the chorales. A number of writers have argued that the librettist was Christian Friedrich Henrici ("Picander"), who often worked with Bach, but his name is missing from the libretto for the first performance, and the absence of the text from the five-volume edition of Picander's poems, which includes less important works, is certainly surprising. Whoever the poet, he must have worked closely with Bach. Not only is the dramaturgical structure of the work rigorous and well balanced, but the new words that were written to fit existing music give the impression of a unified whole. Virtually all the aries and choruses in the Christmas Oratorio come from secular cantatas written for the Saxon royal family. Composed for birthdays and other state occasions, they had served their purpose after a single airing and if they had not been recycled would never have been heard again. And so Bach was able to salvage some first-rate music by underlaying it with new words based on a similar metre. "Tönet, ihr Pauken", for example, became the thematically related "Jauchzet,frohlocket", while Hercules's renunciation of pleasure, "Ich will dich nicht horen", became "Bereite dich, Zion" - on this occasion the sentiments are entirely different. The fact that Bach was able to create a perfect match between words and music is due to his use of stylistic devices familiar from the rhetoric of music and associated not with the actual words but with particular aims such as the expression of joy, yearning or doubt. These stylistic devices are not individual but universal and, hence, are well suited to a work that tells of the birth ofthe Redeemer - an event of truly universal significance.
As is only fitting for a product of the world of Lutheran ideas, the Gospel message in words and music is central to the Christmas Oratorio. For the present recording, a further, strikingly visual element has been added in the form of Austrian Baroque architecture. The recording was made in the Collegiate Church at Waldhausen between the summer and autumn of 198l.With its high barrel-vaulted roof, eight side chapels and magnificently decorated chancel, this church provides an impressive backdrop forthe performance. The great nativity scene in Admont by the Styrian sculptor Josef Stammel was chosen to illustrate the Gospel text. A work of intricate detail, it includes many features of the Christmas story, while the facial expressions and body language of the figures provide a splendid insight into the different reactions triggered by the news of the Infant Jesu's birth. Stammel's work is complemented by a nativity scene from Absam in the Tyrol in which the angel plays a central role. Grass-roots faith - which in the penultimate chorale ("Ich steh an deiner Krippen hier") by Paul Gerhardt is concerned with a Lutheran spiritualization of the events associated with the Christian doctrine of salvation -  acquires particularly devout expression here.
The Waldhausen recording is now more than twenty years old and, as such, is a historical document. If controversy now surrounds certain aspects of the performance, this was not so at the time the recording was made. Nikolaus Harnoncourt has in any case never been concerned with mere matters of formal correctness: "For me a performance is true to the spirit of a work if its supreme aim is to reproduce the substance and content of the work. There is really very little that is more important to me than that."