Complex sentence: The cantata was probablyly based on an earlier lost secular cantata for New Year's Day composed in Köthen (BWV 184a), a duet cantata for soprano and bass with several dance movements.
Split into simpler sentences: The cantata was probablyly based on an earlier secular cantata for New Year's Day (BWV 184a). This work, now lost, was composed in Köthen as a duet cantata for soprano and bass with several dance movements.