Several years into his tenure as music director to the court of Weimar, Johann Sebastian Bach was instructed to write one cantata a month for the chapel services. Near the beginning of this series Bach wrote what was to be his largest sacred Cantata, "Ich hatte viel Bekümmernis," BWV 21. Not only was this work written to go with the readings for the third Sunday after Trinity, but it served as a farewell to the gravely ill Prince Johann Ernst of Sachsen-Weimar. The young prince, who had been one of Bach's favorite and most talented pupils, was on his way to a spa in Swabia where he later died. Bach uses the main tune from a movement of Vivaldi's D Minor Concerto, Opus 3 #11, as the theme for the opening chorus. The concerto had been a favorite of the prince and with its moving text describing a grave illness, the whole movement should be seen as an homage to the young prince.The work itself covers many different styles. The second and last choruses probably date from very early in Bach's career. The opening and the great chorale prelude "Sei nun wieder zufrieden," were written in 1714. Many of the movements were extensively revised for Bach's first Leipzig Cantata cycle in 1723. Certainly the work has a refinement and finish to it unknown in his early Weimar years.The cantata opens with a marvelous sinfonia for oboe and strings. It is virtually a duet between the first violins and the oboe. After the complexity and density of the first chorus, the soprano aria with oboe obbligato "Seufzer, Tränen" is spare and startlingly angular. The tenor recitative and aria returns to the richness of the opening music. These two solo pieces are set to texts of Bach's favorite poet, Salomo Franck. Franck was probably the best contemporary poet that Bach ever set; certainly these intense texts inspired the composer to write some of his greatest music. The first two choruses are from Psalm texts. Between the first and second parts of the cantata was a sermon with further commentary on the designated texts for the third Sunday after Trinity. The second part of the cantata begins with a dialogue between Christ and the Soul. This was a favorite didactic device of Lutheran theology of the period. These dialogues are often associated with the erotic love poetry of the Song of Songs. A popular example are of this genre are the love duets in the cantata "Wachet auf!" Today's cantata was one of the few Bach pieces in Baron von Swieten's library in Vienna. Clearly Mozart saw this piece there, for the duet is inspiration for both "La ci darem" from Don Giovanni and the third act Susanna-Count duet from Le Nozze di Figaro.