Rossini's first opera, Demetrio e Polibio (Demetrius and Polybius) was written in 1808. A dramma serio in two acts, it was first performed at the Teatro Valle in Rome on 18th May 1812. It deals with the enmity between the kings of Syria and Parthia and the love of their daughter and son.
The overture summons attention at the start, followed by a gently lyrical bassoon melody which leads to the livelier principal melody, stated first by the oboe, and the second subject, entrusted to the bassoon. Diabelli, for a piano reduction published in Vienna, found it necessary to make certain adjustments to regularise the form of the recapitulation.