Richard Wagner; Der Ring des Nibelungen

Richard Wagner's vast Der Ring des Nibelungen cycle comprises four full-length operas (Das Rheingold, Die Walkure, Siegfried and Gotterdammerung) and is arguably the most extraordinary achievement in the history of opera. His own libretto to the operas is an intricate system of metric patterns, imaginative metaphors and alliteration, combining to produce the music in text.