About the work
Demetrio e Polibio is a dramma serio in two acts and Rossini's first complete opera: the tenor Domenico Mombelli commissioned it for his own family, and his wife Vincenzina Viganò Mombelli wrote the libretto. Rossini composed it in stages between 1806 and 1809 while a student at Bologna's Liceo Musicale; a private first performance by the Mombelli family took place in 1809 without the composer present, and the public premiere followed only on 18 May 1812 at the Teatro Valle in Rome.
Plot
At the court of the Parthian king Polibio grows up young Siveno, in truth the presumed-dead son of the Syrian king Demetrio, who loves Polibio's daughter Lisinga. When a Syrian envoy demands the boy's return and has Lisinga abducted, he reveals himself to be Demetrio. The recognition resolves the conflict: Siveno and Lisinga are allowed to marry, and the once-warring royal houses reconcile.
Cultural significance
Although chronologically Rossini's first opera, it remained little known in his lifetime, having been written only for the Mombelli family's private circle; La cambiale di matrimonio of 1810 is usually regarded as his actual stage debut. Even so, the work already shows the young composer's assured sense of melody and ensemble writing.