Ifigenia en Aulide

Iphigénie en Aulide (Iphigeneia in Aulis) is an opera in three acts by Christoph Willibald Gluck, the first work he wrote for the Paris stage. The libretto was written by Leblanc du Roullet and was based on Jean Racine's tragedy Iphigénie. It was premiered at the Paris Opéra on 19 April 1774.
Iphigénie was premiered at the Paris Opéra on 19 April 1774, and "did not prove popular at first, although its overture was applauded generously from the start. it was billed on 22, 24 and 29 April only to have its first run interrupted by the 1 May to 15 June 1774 closing of the theatre on account of the illness and death of Louis XV ... Iphigénie en Aulide was not returned to the stage until 10 January 1775, but it was revived annually in 1776-1780, 1782-1793, 1796-1824. It was mounted in Paris more than 400 times in this interval of 50 years", and eventually turned out to be Gluck's most frequently performed opera in Paris. For the 1775 revival, "Gluck revised Iphigénie en Aulide ... introducing the goddess Diana (soprano) at the end of the opera as a dea ex machina, and altering and expanding the divertissements... So, broadly speaking, there are two versions of the opera; but the differences are by no means so great or important as those between Orfeo ed Euridice and Orphée et Euridice or between the Italian and the French Alceste".