Beethoven wrote this work around the time he was concluding studies in vocal composition with Antonio Salieri. The older master was teaching him specifically how to set Italian text to music. It is hardly surprising that Beethoven learned his craft well, but this duet apparently did not satisfy him, since he withheld it. As a result it not only remained unpublished throughout his lifetime, but it languished in almost total obscurity until 1939, when it was premiered. Ironically, this duet is a high quality composition, fully deserving of greater attention.
Beethoven uses a text by Pietro Metastasio (1698-1782) from Act I, scene 10, of his Olimpiade, which consists of an exchange between two lovers. Beethoven marked the opening section Adagio, and the music and vocal writing here are quite lovely. The orchestral accompaniment is especially imaginative throughout the whole piece. Beethoven scored the work for strings, pairs of flutes, oboes, bassoons, and horns, wringing much color and atmosphere from the chamber-sized ensemble. Following the Adagio, the tempo switches to Allegro and the mood becomes more dramatic and charged. This latter section contains much of the mature Beethoven, auguring Fidelio and giving an intensity to the piece that elevates it nearly to that inspired level.
The work closes with a brief coda that Beethoven wrote as a replacement for the original one, which was less thematically tied to the previous material.