Durchlauchtster Leopold, BWV 173a

Bach composed the cantata for performance in Köthen to celebrate the birthday of Leopold von Anhalt-Köthen.

Some of them are lost, while others such as Der Himmel dacht auf Anhalts Ruhm und Glück, BWV 66.1 can be reconstructed because Bach reused the music later.

[2] The cantata is scored for two vocal soloists (soprano and bass), two flauto traverso, bassoon, two violins, viola and basso continuo including violone and harpsichord.

Movement 1 is accompanied by the strings and leads to a virtuoso coloratura on the da capo of the first line, addressing Leopold.

[5] The structure of this duet is unique in Bach's cantatas, the variations in rising keys, and the increase in instruments and musical texture all adding up to illustrate the exaltation of the addressee.

Movement 7 is in great contrast set for only low voice and instruments, bassoon and cello in unison to a continuo played by violone and harpsichord.