Mozart's "La clemenza di Tito" Premieres

La clemenza di Tito (The Clemency of Titus), K. 621, is an opera seria composed by Wolfgang Amadeus Mozart, with text after Metastasio. It was started after the bulk of The Magic Flute, the last opera that Mozart worked on, was already written (Mozart completed The Magic Flute after the Prague premiere of Tito).

http://en.wikipedia.org/wiki/La_clemenza_di_Tito