Let us illustrate Wagner's mature use of Leitmotif by the theme which happens to be associated with Alberich's ring.
A famous and typical instance of Wagner's use of Leitmotif in tragic irony is the passage where Hagen gives Siegfried friendly welcome, to the melody of the curse which Alberich pronounced on the ring and all who approached it.
The more subtle examples are inexhaustible in variety and resource; and perhaps the climax of subtlety is the almost entire absence of Leitmotif in the first scene of the third act of Gotterddmmerung, when Siegfried throws away his last chance of averting his doom.
The method of presentation in both symphonies is by means of representative themes (Leitmotif), and their combination and interaction.
This curse, the Leitmotif of the whole story, began to operate at once.