The legend portrays Tannhauser as a knight and poet who found the Venusberg, the subterranean mountain home of Venus, and spent a year there worshipping the goddess. After leaving the Venusberg, Tannhuser is filled with remorse, and travelled to Rome to ask Pope Urban IV if it would be possible to be absolved of his sins. Urban replies that forgiveness is as impossible as it would be for his papal staff to blossom. Three days after Tannhauser's departure Urban's staff blooms with flowers; messengers are sent to retrieve the knight, but he has already returned to Venusberg, never to be seen again.
This was made famous in Wagner's opera Tannhauser in 1845.