In Wagner’s opera Das Rheingold, Alberich steals the Rhine gold.
The opera opens with three Rhinemaidens guarding the gold beneath the river. They tell Alberich that only someone who renounces love can take it. Alberich accepts that condition, seizes the gold, and later has it forged into a ring with immense power.
Alberich is the ruler of the Nibelungs, a race of underground smiths. His theft sets the central conflict of Wagner’s four-part Ring cycle in motion. The gods later obtain the ring from Alberich’s son, the dwarf Mime’s brother, through a chain of bargains and deception.
A common mix-up is confusing Alberich with Wotan, the chief god. Wotan does not steal the gold; he takes the completed ring from the giant Fafner, who acquired it as payment for building Valhalla. Wagner adapted these figures and events from medieval Germanic and Norse legend, especially material related to the Nibelung tradition.