Wagner completed the first draft of Siegfrieds Tod, later renamed Götterdämmerung in October 1848. Realizing that much knowledge of the situation was preassumed, he added a Prologue, and eventually turned the project into a cycle of four operas. He changed the dramatic focus from Siegfried to Wotan, and consequently had to revise Siegfrieds Tod. In 1852, he changed the end so that Walhall and the gods were destroyed. In 1856, more changes were made in light of his reading of Schopenhauer and interest in Buddhism. The first complete draft of the score was completed in April 1872, and the entire opera finally completed on November 21, 1874.
Götterdämmerung is a colossal work, one of the longest evenings of opera in the standard repertory. The Prologue and Act One, connected by the orchestral "Siegfried's Rhine Journey" probably comprise the longest continuous stretch of music heard in any operatic work. Despite this, the drama is so compressed that events seem almost to race to their cataclysmic end. Götterdämmerung's structure echoes that of the entire cycle, with a prologue and three acts reflecting the large-scale plan of the prologue and three evenings.
Musically, Wagner has gained such mastery of his drama and musical motives, that he treats both with superb fluidity. At the same time, there seem to be regressive moments. For example, the Act Two chorus of the Gibichung vassals seems like an artifact of the old grand opera, as does the revenge trio in the same act, with its ensemble singing, and duplications of text. These events are partially explained by the libretto having preceded the music by more than 20 years, from a time when Wagner's music-dramatic theories had not been fully realized.
Wagner's use of his Leitmotives produces uncannily powerful psychological effects. For example, in Act Three, at the moment of Siegfried's death, the audience sees what he sees, by the use of Brünnhilde's awakening music from Siegfried Act Three, which then fades with his consciousness. It has been observed that the audience's memory for dramatic narrative have been stretched almost to their limits by the arc between these two moments; but an even longer stretch comes when the Funeral Music begins with the timpani strokes from Brünnhilde's annunciation of Siegmund's death in Die Walküre.
The music following Brünnhilde's immolation, even if it does not "explain" anything, is hugely consoling after the multiple tragedies, and that consoling effect again lies in Wagner's masterful manipulation of memory. Over a simmering stew of Leitmotives -- those of the Rhine, Walhall, and Siegfried -- the violins sing an arching melody first heard in Die Walküre, when Sieglinde burst out with this melody after Brünnhilde told her that she was bearing Siegmund's child. The label traditionally attached to this melody, "Redemption by Love," has misled audiences; in fact, Wagner considered it a song of praise to his heroine, Brünnhilde. His choice to end the entire vast work with this melody is indeed explanatory.