Question: Which opera is by Christoph Willibald Gluck, Iphigénie en Tauride or Der Barbier von Bagdad?
Sentence (from "Iphigénie en Tauride"): Iphigénie en Tauride ("Iphigenia in Tauris") is a 1779 opera by Christoph Willibald Gluck in four acts.
Relevant evidence: Yes