Christian Friedrich Henrici, writing under the pen name Picander, was Bach's most prolific collaborator and the librettist of the St. Matthew Passion. In 1728–29, he published a complete set of cantata texts for the liturgical year, explicitly intended for Bach to set to music.

The fate of this cycle is one of the great mysteries of Bach scholarship. Picander's texts survive in print, but most of the music is lost. Only around a dozen cantatas can be securely attributed to this cycle — the rest may have perished, or may yet be rediscovered among unattributed works.

What survives shows a mature partnership: Picander's poetry is more dramatic and psychologically nuanced than earlier librettists, and Bach's settings respond with music of corresponding depth.