Admirers of Gluck the reformer may be surprised by this thoroughly Baroque, extremely florid opera composed by him in 1765 (three years after Orfeo ed Euridice changed the landscape of opera forever). La corona , Gluck's setting of Metastasio's one-act azione teatrale (the master librettist's own term for a serenata with a plot), was commissioned by Queen Maria Theresa as a name-day gift for the emperor. Though is also styled an azione teatrale , the two operas could hardly be more different. Considering that La corona contains as treacherously difficult a collection of florid arias as can be found in any score of the period, it's hard to credit that it was created specifically to be sung by the three royal princesses; even the most adept prime donne of the period would have struggled to master its score. Due to the sudden death of the emperor, La corona was shelved and never performed in Gluck's lifetime. Atypically for a score of this quality and complexity, the composer mined relatively little of it for future works, with a notable exception in his transformation of the second part of the overture into the love duet in Paride ed Elena .