Who wrote the four operas in "The Ring of the Nibelung" (Der Ring des Nibelungen)?

Explanation

Wilhelm Richard Wagner (1813-1883) was a German composer, best known for his operas. Wagner was born in Leipzig and died in Venice. He wrote "Der fliegende Holländer" (1843), "Tristan und Isolde" (1865), "Parsifal" (1822) and the four operas in the "Der Ring des Nibelungen" (1848-1874): "Das Rheingold", "Die Walküre", "Siegfried" and "Götterdämmerung". The tetralogy is based on characters and themes from Norse mythology.