Demofoonte (Leo, Leonardo)
After manuscript in Biblioteca del Conservatorio San Pietro a Majella. - According to the title page of the score, the opera is a pasticcio, with Act I composed by Domenico Sarro, Act II by Francesco Mancini and Act III by Leonardo Leo, but it is doubtful if the score really gives this original version (the first performance of Metastasio's drama in Italy). Two pieces from Act II, the aria "Se tutti i mali miei" presented here and the duet "La destra ti chiedo" also appear as single items in numerous aria collections where they are always attributed to Leo who also used them again in "Demetrio". It may be possible that Leo later set the whole libretto two his own music and that the Neapolitan score represents this "all-Leo" Demofoonte, with only the final aria of Act I ("Se ardire e speranza") taken from the original Act I by Domenico Sarro (or Sarri; it is marked "Sarri" in the manuscript).
Last movement of the overture appears to be incomplete. If anyone has a different copy of that I'll be happy to complete it here (did not want to try and re-create an ending).
The opera actually is a pasticcio. The first act is by Francesco Mancini, the second by Domenico Sarro and the third one by Leonardo Leo.