The Christmas Oratorio (German: Weihnachtsoratorium), , is an oratorio by Johann Sebastian Bach intended for performance in church during the Christmas season. It is in six parts, each part a cantata intended for performance in a church service on a feast day of the Christmas period. It was written for the Christmas season of 1734 and incorporates music from earlier compositions, including three secular cantatas written during 1733 and 1734 and a largely lost church cantata, BWV 248a. The date is confirmed in Bach's autograph manuscript. The next complete public performance was not until 17 December 1857 by the Sing-Akademie zu Berlin under Eduard Grell. The Christmas Oratorio is a particularly sophisticated example of parody music. The author of the text is unknown, although a likely collaborator was Christian Friedrich Henrici (Picander). The work belongs to a group of three oratorios written in 1734 and 1735 for major feasts, the other two works being the Ascension Oratorio (BWV 11) and the Easter Oratorio (BWV 249). All three of these oratorios to some degree parody earlier compositions. The Christmas Oratorio is by far the longest and most complex work of the three. The first part (for Christmas Day) describes the Birth of Jesus, the second (for 26 December) the annunciation to the shepherds, the third (for 27 December) the adoration of the shepherds, the fourth (for New Year's Day) the circumcision and naming of Jesus, the fifth (for the first Sunday after New Year) the journey of the Magi, and the sixth (for Epiphany) the adoration of the Magi. The running time for the entire oratorio is around three hours. In concert performance, it is often presented split into two parts. History In the liturgical calendar of the German reformation era in Saxony, the Christmas season started on 25 December (Christmas Day) and ended on 6 January (Epiphany). It was preceded by Advent, and followed by the period of the Sundays after Epiphany. It included at least three feast days that called for festive music during religious services: apart from Christmas (Nativity of Christ) and Epiphany (Visit of the Magi) the period also included New Year's Day (1 January), in Bach's time still often referred to as the Feast of the Circumcision of Christ. Also 26 and 27 December (second and third day of Christmas) were commonly considered feast days, with festive music in church. If a Sunday fell between 27