Short answers, pulled from the story.
Wolfgang Amadeus Mozart composed the opera Lucio Silla when he was 16 years old during a single year in 1772. The work premiered on the 26th of December 1772 inside the Teatro Regio Ducale in Milan.
Giovanni de Gamerra provided the original libretto for the opera Lucio Silla though Pietro Metastasio revised it later. Other composers including Handel Leonardo Vinci Pasquale Anfossi and Johann Christian Bach also created operas with similar titles covering the same historical subject matter.
The UK premiere of the opera Lucio Silla took place much later than the original performance at Camden Town Hall in London in 1967. A US premiere followed shortly after in 1968 with a staging in Baltimore.
This opera marked the first of Wolfgang Amadeus Mozart's stage works to feature devotion to recitativo accompagnato or accompanied recitative. The orchestration proved more ambitious than the composer's earlier Milanese opera Mitridate re di Ponto with obbligato parts appearing frequently within the arias themselves.
A 1980 version recorded by Salzburg featured Júlia Várady as Cecilio Arleen Augér as Giunia Helen Donath singing Celia and Peter Schreier playing Lucio Silla. Werner Krenn performed Aufidio while Edith Mathis took Lucio Cinna for this Deutsche Grammophon release.