Bach's recycled choral music brings festive cheer to Leipzig

Shout, exult, arise, praise these days! Glorify what the Almighty today has done!' Early on the morning of 25 December 1734, these words resounded from the choir stalls of the Thomaskirche, Leipzig, to a jubilant accompaniment of festive timpani, pealing trumpets and scampering violins. Seated at a keyboard, the church's director of music Johann Sebastian Bach marshalled the musicians in a performance of the cantata Jauchzet, frohlocket! Auf, preiset die Tage, which preceded the sermon in the morning service.

- Terry Blain

Jauchzet, frohlocket! was the first of six cantatas Bach had specially assembled for that year's Christmas season, a cycle collectively titled the Weihnachtsoratorium (Christmas Oratorio) which told the story of Christ’s birth in Bethlehem. As the exuberant opening movement echoed round the building, some in the congregation may well have experienced glimmers of recognition. The music seemed somehow familiar: could they possibly have heard it before?

The answer was yes. A year earlier Bach had written a cantata (Tönet, ihr Pauken! Erschallet, Trompeten!) for the birthday of Maria Josepha, Queen of Poland and Electress of Saxony, and performed it at a coffee house on Leipzig's fashionable Katharinenstrasse. Four of its movements resurfaced a year later, with new words, in the Christmas Oratorio. Three more of Bach's cantatas had movements similarly cut-and-pasted to the Oratorio, and in total around 20 of its 64 movements were taken from previously performed works and were not newly composed music.

Why did Bach do this? Why borrow 'old' material when he could have written new? One theory is that, pushed for time, he used recycling as a way of putting the