After the strict discipline of the chorale cantata cycle, Bach's third year in Leipzig sees a loosening of formal constraints and a new spirit of experimentation. Multiple librettists contribute texts — including Mariane von Ziegler, one of the few women to write cantata poetry for Bach.

The forms are more varied: solo cantatas become more frequent, Italian-style da capo arias grow more elaborate, and recitatives take on a heightened dramatic intensity. Some of the most introspective and emotionally complex cantatas belong to this period.

The cycle is less complete than the first two — Bach was increasingly occupied with other duties, and may have repeated earlier cantatas for some Sundays. But individual works like Ich will den Kreuzstab gerne tragen (BWV 56) and Vergnügte Ruh (BWV 170) rank among his finest.