Are both Eine florentinische Tragödie and Alceste operas?
Alceste (Gluck) Alceste, Wq. 37 (the later French version is Wq. 44), is an opera by Christoph Willibald Gluck from 1767. The libretto (in Italian) was written by Ranieri de' Calzabigi and based on the play "Alcestis" by Euripides. The premiere took place on 26 December 1767 at the Burgtheater in Vienna.
Motezuma Motezuma is an opera in three acts by Antonio Vivaldi with an Italian libretto by Alvise Giusti. The libretto is very loosely based on the life of the Aztec ruler Montezuma who died in 1520. The first performance was given in the Teatro Sant'Angelo in Venice on 14 November 1733. (In earlier reference books the opera is referred to as "Montezuma", but since the reappearance of the original manuscript this has been corrected to "Motezuma".) The music was thought to have been lost, but was discovered in 2002 in the archive of the music library of the Sing-Akademie zu Berlin. Its first fully staged performance in modern times took place in Düsseldorf, Germany, on 21 September 2005.